document_title: Heavy water

question_text: at what temperature would a sample of heavy water freeze

question_tokens: at what temperature would a sample of heavy water freeze

text: Heavy water

text: Explanation[edit]

text: Deuterium is a hydrogen isotope with a nucleus containing a neutron and a proton; the nucleus of a protium (normal hydrogen) atom consists of just a proton. The additional neutron makes a deuterium atom roughly twice as heavy as a protium atom.

text: A molecule of heavy water has two deuterium atoms in place of the two protium atoms of ordinary "light" water. The weight of a heavy water molecule, however, is not substantially different from that of a normal water molecule, because about 89% of the molecular weight of water comes from the single oxygen atom rather than the two hydrogen atoms. The colloquial term heavy water refers to a highly enriched water mixture that contains mostly deuterium oxide D2O, but also some hydrogen-deuterium oxide (HDO) and a smaller number of ordinary hydrogen oxide H2O molecules. For instance, the heavy water used in CANDU reactors is 99.75% enriched by hydrogen atom-fraction—meaning that 99.75% of the hydrogen atoms are of the heavy type. For comparison, ordinary water (the "ordinary water" used for a deuterium standard) contains only about 156 deuterium atoms per million hydrogen atoms, meaning that 0.0156% of the hydrogen atoms are of the heavy type.

text: Heavy water is not radioactive. In its pure form, it has a density about 11% greater than water, but is otherwise physically and chemically similar. Nevertheless, the various differences in deuterium-containing water (especially affecting the biological properties) are larger than in any other commonly occurring isotope-substituted compound because deuterium is unique among heavy stable isotopes in being twice as heavy as the lightest isotope. This difference increases the strength of water's hydrogen-oxygen bonds, and this in turn is enough to cause differences that are important to some biochemical reactions. The human body naturally contains deuterium equivalent to about five grams of heavy water, which is harmless. When a large fraction of water (> 50%) in higher organisms is replaced by heavy water, the result is cell dysfunction and death.[4]

text: Heavy water was first produced in 1932, a few months after the discovery of deuterium.[5] With the discovery of nuclear fission in late 1938, and the need for a neutron moderator that captured few neutrons, heavy water became a component of early nuclear energy research. Since then, heavy water has been an essential component in some types of reactors, both those that generate power and those designed to produce isotopes for nuclear weapons. These heavy water reactors have the advantage of being able to run on natural uranium without using graphite moderators that pose radiological[6] and dust explosion[7] hazards in the decommissioning phase. Most modern reactors use enriched uranium with ordinary water as the moderator.

text: Other heavy forms of water[edit]

text: Semiheavy water[edit]

text:
Semiheavy water, HDO, exists whenever there is water with light hydrogen (protium, 1H) and deuterium (D or 2H) in the mix. This is because hydrogen atoms (hydrogen-1 and deuterium) are rapidly exchanged between water molecules. Water containing 50% H and 50% D in its hydrogen actually contains about 50% HDO and 25% each of H2O and D2O, in dynamic equilibrium.
In normal water, about 1 molecule in 3,200 is HDO (one hydrogen in 6,400 is in the form of D), and heavy water molecules (D2O) only occur in a proportion of about 1 molecule in 41 million (i.e. one in 6,4002). Thus semiheavy water molecules are far more common than "pure" (homoisotopic) heavy water molecules.

text: Heavy-oxygen water[edit]

text: Water enriched in the heavier oxygen isotopes 17O and 18O is also commercially available, e.g., for use as a non-radioactive isotopic tracer. It is "heavy water" as it is denser than normal water (H218O is approximately as dense as D2O, H217O is about halfway between H2O and D2O)—but is rarely called heavy water, since it does not contain the deuterium that gives D2O its unusual nuclear and biological properties. It is more expensive than D2O due to the more difficult separation of 17O and 18O.[8] H218O is also used for production of fluorine-18 for radiopharmaceuticals and radiotracers and for positron emission tomography.

text: Tritiated water[edit]

text: Tritiated water contains tritium (3H) in place of protium (1H) or deuterium (2H), and therefore it is radioactive.

text: Physical properties[edit]

text:
Physical properties of isotopologues of water[9]

Property
D2O (Heavy water)
HDO (Semiheavy water)
H2O (Light water)

Freezing point
3.82 °C (38.88 °F) (276.97 K)
2.04 °C (35.67 °F) (275.19 K)
0.0 °C (32 °F) (273.15 K)

Boiling point
101.4 °C (214.5 °F) (374.55 K)
100.7 °C (213.3 °F) (373.85 K)
100.0 °C (212 °F) (373.15 K)

Density at STP (g/mL)
1.1056
1.054
0.9982

Temp. of maximum density
11.6 °C
Unverified
3.98 °C[10]

Dynamic viscosity (at 20 °C, mPa·s)
1.2467
1.1248
1.0016

Surface tension (at 25 °C, N/m)
0.07187
0.07193
0.07198

Heat of fusion (kJ/mol)
6.132
6.227
6.00678

Heat of vaporisation (kJ/mol)
41.521
Unverified

40.657

pH (at 25 °C)[11]
7.44 ("pD")
7.266 ("pHD")
7.0

pKb (at 25 °C)[11]
7.44 ("pKb D2O")
Unverified
7.0

Refractive index (at 20 °C, 0.5893 μm)[12]
1.32844
Unverified
1.33335

text: The physical properties of water and heavy water differ in several respects. Heavy water is less dissociated than light water at given temperature, and the true concentration of D+ ions is less than  H+ ions would be for a light water sample at the same temperature. The same is true of OD− vs.  OH− ions. For heavy water Kw D2O (25.0 °C) = 1.35 × 10−15, and [D+ ] must equal [OD− ] for neutral water. Thus pKw D2O = p[OD−] + p[D+] = 7.44 + 7.44 = 14.87 (25.0 °C), and the p[D+] of neutral heavy water at 25.0 °C is 7.44.

text: The pD of heavy water is generally measured using pH electrodes giving a pH (apparent) value, or pHa, and at various temperatures a true acidic pD can be estimated from the directly pH meter measured pHa, such that pD+ = pHa (apparent reading from pH meter) + 0.41.  The electrode correction for alkaline conditions is 0.456 for heavy water. The alkaline correction is then pD+ = PHa(apparent reading from pH meter) + 0.456. These corrections are slightly different from the differences in p[D+] and p[OD-] of 0.44 from the corresponding ones in heavy water.[13]

text: Heavy water is 10.6% denser than ordinary water, and heavy water's physically different properties can be seen without equipment if a frozen sample is dropped into normal water, as it will sink. If the water is ice-cold the higher melting temperature of heavy ice can also be observed: it melts at 3.7 °C, and thus does not melt in ice-cold normal water.[14]

text: An early experiment reported not the "slightest difference" in taste between ordinary and heavy water.[15] However, rats given a choice between distilled normal water and heavy water were able to avoid the heavy water based on smell, and it may have a different taste.[16]

text: No physical properties are listed for "pure" semi-heavy water, because it is unstable as a bulk liquid. In the liquid state, a few water molecules are always in an ionised state, which means the hydrogen atoms can exchange among different oxygen atoms. Semi-heavy water could, in theory, be created via a chemical method, but it would rapidly transform into a dynamic mixture of 25% light water, 25% heavy water, and 50% semi-heavy water.  However, if it were made in the gas phase and directly deposited into a solid, semi heavy water in the form of ice could be stable. This is due to collisions between water vapour molecules being almost completely negligible in the gas phase at standard temperatures, and once crystallized collisions between the molecules cease altogether due to the rigid lattice structure of solid ice.[citation needed]

text: History[edit]

text:
Harold Urey discovered the isotope deuterium in 1931 and was later able to concentrate it in water.[17] Urey's mentor Gilbert Newton Lewis isolated the first sample of pure heavy water by electrolysis in 1933.[18] George de Hevesy and Erich Hofer used heavy water in 1934 in one of the first biological tracer experiments, to estimate the rate of turnover of water in the human body.[19] The history of large-quantity production and use of heavy water in early nuclear experiments is given below.[20]
Emilian Bratu and Otto Redlich studied the autodissociation of heavy water in 1934.[21]

text: Effect on biological systems[edit]

text: Different isotopes of chemical elements have slightly different chemical behaviors, but for most elements the differences are far too small to use, or even detect. For hydrogen, however, this is not true. The larger chemical isotope-effects seen between protium (light hydrogen) versus deuterium and tritium manifest because bond energies in chemistry are determined in quantum mechanics by equations in which the quantity of reduced mass of the nucleus and electrons appears. This quantity is altered in heavy-hydrogen compounds (of which deuterium oxide is the most common) more than for heavy-isotope substitution in other chemical elements. This isotope effect of heavy hydrogen is magnified further in biological systems, which are very sensitive to small changes in the solvent properties of water.

text: Heavy water is the only known chemical substance that affects the period of circadian oscillations, consistently increasing the length of each cycle. The effect is seen in unicellular organisms, green plants, isopods, insects, birds, mice, and hamsters. The mechanism is unknown.[22]

text: To perform their tasks, enzymes rely on their finely tuned networks of hydrogen bonds, both in the active center with their substrates, and outside the active center, to stabilize their tertiary structures. As a hydrogen bond with deuterium is slightly stronger[23] than one involving ordinary hydrogen, in a highly deuterated environment, some normal reactions in cells are disrupted.

text: Particularly hard-hit by heavy water are the delicate assemblies of mitotic spindle formation necessary for cell division in eukaryotes. Plants stop growing and seeds do not germinate when given only heavy water, because heavy water stops eukaryotic cell division.[24][25]  The deuterium cell is larger and it is a modification of the direction of division.[26][27] The cell membrane also changes, and it reacts first to the impact of heavy water. In 1972 it was demonstrated that an increase in the percentage content of deuterium in water reduces plant growth.[28] Research conducted on the growth of prokaryote microorganisms in artificial conditions of a heavy hydrogen environment showed that in this environment, all the hydrogen atoms of water could be replaced with deuterium.[29][30][31] Experiments showed that bacteria can live in 98% heavy water.[32] However, all concentrations over 50% of deuterium in the water molecules were found to kill plants.

text: Effect on animals[edit]

text: Experiments in mice, rats, and dogs[33] have shown that a degree of 25% deuteration causes (sometimes irreversible) sterility, because neither gametes nor zygotes can develop. High concentrations of heavy water (90%) rapidly kill fish, tadpoles, flatworms, and Drosophila. Mammals (for example, rats) given heavy water to drink die after a week, at a time when their body water approaches about 50% deuteration.[34] The mode of death appears to be the same as that in cytotoxic poisoning (such as chemotherapy) or in acute radiation syndrome (though deuterium is not radioactive), and is due to deuterium's action in generally inhibiting cell division. It is more toxic to malignant cells than normal cells but the concentrations needed are too high for regular use.[33] As in chemotherapy, deuterium-poisoned mammals die of a failure of bone marrow (bleeding and infection) and intestinal-barrier functions (diarrhea and fluid loss).

text: Despite the problems of plants and animals in living with too much deuterium, prokaryotic organisms such as bacteria, which do not have the mitotic problems induced by deuterium, may be grown and propagated in fully deuterated conditions, resulting in replacement of all hydrogen atoms in the bacterial proteins and DNA with the deuterium isotope.[33][35]

text: Full replacement with heavy atom isotopes can be accomplished in higher organisms with other non-radioactive heavy isotopes (such as carbon-13, nitrogen-15, and oxygen-18), but this cannot be done for the stable heavy isotope of hydrogen.[citation needed]

text: Deuterium oxide is used to enhance boron neutron capture therapy, but this effect does not rely on the biological effects of deuterium per se, but instead on deuterium's ability to moderate (slow) neutrons without capturing them.[33]

text: Toxicity in humans[edit]

text: Because it would take a very large amount of heavy water to replace 25% to 50% of a human being's body water (water being in turn 50–75% of body weight[36]) with heavy water, accidental or intentional poisoning with heavy water is unlikely to the point of practical disregard. Poisoning would require that the victim ingest large amounts of heavy water without significant normal water intake for many days to produce any noticeable toxic effects.

text: Oral doses of heavy water in the range of several grams, as well as heavy oxygen 18O, are routinely used in human metabolic experiments. See doubly labeled water testing. Since one in about every 6,400 hydrogen atoms is deuterium, a 50 kg human containing 32 kg of body water would normally contain enough deuterium (about 1.1 g) to make 5.5 g of pure heavy water, so roughly this dose is required to double the amount of deuterium in the body.

text: A loss of blood pressure may partially explain the reported incidence of dizziness upon ingestion of heavy water. However, it is more likely that this symptom can be attributed to altered vestibular function.[37]

text: Heavy water radiation contamination confusion[edit]

text: Although many people associate heavy water primarily with its use in nuclear reactors, pure heavy water is not radioactive. Commercial-grade heavy water is slightly radioactive due to the presence of minute traces of natural tritium, but the same is true of ordinary water. Heavy water that has been used as a coolant in nuclear power plants contains substantially more tritium as a result of neutron bombardment of the deuterium in the heavy water (tritium is a health risk when ingested in large quantities).

text: In 1990, a disgruntled employee at the Point Lepreau Nuclear Generating Station in Canada obtained a sample (estimated as about a "half cup") of heavy water from the primary heat transport loop of the nuclear reactor, and loaded it into a cafeteria drink dispenser. Eight employees drank some of the contaminated water. The incident was discovered when employees began leaving bioassay urine samples with elevated tritium levels. The quantity of heavy water involved was far below levels that could induce heavy water toxicity, but several employees received elevated radiation doses from tritium and neutron-activated chemicals in the water.[38] This was not an incident of heavy water poisoning, but rather radiation poisoning from other isotopes in the heavy water. Some news services were not careful to distinguish these points, and some of the public were left with the impression that heavy water is normally radioactive and more severely toxic than it is. Even if pure heavy water had been used in the water cooler indefinitely, it is not likely the incident would have been detected or caused harm, since no employee would be expected to get much more than 25% of their daily drinking water from such a source.[39]

text: Production[edit]

text: On Earth, deuterated water, HDO, occurs naturally in normal water at a proportion of about 1 molecule in 3,200. This means that 1 in 6,400 hydrogen atoms is deuterium, which is 1 part in 3,200 by weight (hydrogen weight). The HDO may be separated from normal water by distillation or electrolysis and also by various chemical exchange processes, all of which exploit a kinetic isotope effect. (For more information about the isotopic distribution of deuterium in water, see Vienna Standard Mean Ocean Water.)  In theory, deuterium for heavy water could be created in a nuclear reactor, but separation from ordinary water is the cheapest bulk production process.

text: The difference in mass between the two hydrogen isotopes translates into a difference in the zero-point energy and thus into a slight difference in the speed of the reaction. Once HDO becomes a significant fraction of the water, heavy water becomes more prevalent as water molecules trade hydrogen atoms very frequently. Production of pure heavy water by distillation or electrolysis requires a large cascade of stills or electrolysis chambers and consumes large amounts of power, so the chemical methods are generally preferred.

text: The most cost-effective process for producing heavy water is the dual temperature exchange sulfide process (known as the Girdler sulfide process) developed in parallel by Karl-Hermann Geib and Jerome S. Spevack in 1943.[40]

text: An alternative process,[41] patented by Graham M. Keyser, uses lasers to selectively dissociate deuterated hydrofluorocarbons to form deuterium fluoride, which can then be separated by physical means. Although the energy consumption for this process is much less than for the Girdler sulfide process, this method is currently uneconomical due to the expense of procuring the necessary hydrofluorocarbons.

text: As noted, modern commercial heavy water is almost universally referred to, and sold as, deuterium oxide. It is most often sold in various grades of purity, from 98% enrichment to 99.75–99.98% deuterium enrichment (nuclear reactor grade) and occasionally even higher isotopic purity.

text: Argentina[edit]

text:
Argentina is the main producer of heavy water, using an ammonia/hydrogen exchange based plant supplied by Switzerland's Sulzer company. It is also a major exporter to Canada, USA, Germany, and other countries. The heavy water production facility located at Arroyito, Neuquén Province is the world's largest heavy water production facility. Argentina produces 200 tons of heavy water per year using, not H2S bithermal method, but monothermal ammonia-hydrogen isotopic
exchange.[42][43][44][45][46]

text: Soviet Union[edit]

text: In October 1939, Soviet physicists Yakov Borisovich Zel'dovich and  Yulii Borisovich Khariton concluded that heavy water and carbon were the only feasible moderators for a natural uranium reactor, and in August 1940, along with Georgy Flyorov, submitted a plan to the Russian Academy of Sciences calculating that 15 tons of heavy water were needed for a reactor.  With the Soviet Union having no uranium mines at the time, young Academy workers were sent to Leningrad photographic shops to buy uranium nitrate, but the entire heavy water project was halted in 1941 when German forces invaded during Operation Barbarossa.

text: By 1943, Soviet scientists had discovered that all scientific literature relating to heavy water had disappeared from the West, which Flyorov in a letter warned Soviet leader Joseph Stalin about,[47] and at which time there was only 2–3 kg of heavy water in the entire country.  In late 1943, the Soviet purchasing commission in the U.S. obtained 1 kg of heavy water and a further 100 kg in February 1945, and upon World War II ending, the NKVD took over the project.

text: In October 1946, as part of the Russian Alsos, the NKVD deported to the Soviet Union from Germany the German scientists who had worked on heavy water production during the war, including Karl-Hermann Geib, the inventor of the Girdler sulfide process.[48]  These German scientists worked under the supervision of German physical chemist Max Volmer at the Institute of Physical Chemistry in Moscow with the plant they constructed producing large quantities of heavy water by 1948.[40][49]

text: United States[edit]

text: During the Manhattan Project the United States constructed three heavy water production plants as part of the P-9 Project at Morgantown Ordnance Works, near Morgantown, West Virginia; at the Wabash River Ordnance Works, near Dana and Newport, Indiana; and at the Alabama Ordnance Works, near Childersburg and Sylacauga, Alabama. Heavy water was also acquired from the Cominco plant in Trail, British Columbia, Canada. The Chicago Pile-3 experimental reactor used heavy water as a moderator and went critical in 1944. The three domestic production plants were shut down in 1945 after producing around 20 metric tons of product[citation needed] (around 20,000 litres).[50] The Wabash plant was reopened and began resumption of heavy water production in 1952.

text: In 1953, the United States began using heavy water in plutonium production reactors at the Savannah River Site. The first of the five heavy water reactors came online in 1953, and the last was placed in cold shutdown in 1996. The SRS reactors were heavy water reactors so that they could produce both plutonium and tritium for the US nuclear weapons program.

text: The U.S. developed the Girdler sulfide chemical exchange production process—which was first demonstrated on a large scale at the Dana, Indiana plant in 1945 and at the Savannah River Plant, South Carolina in 1952. DuPont operated the SRP for the USDOE until 1 April 1989, when Westinghouse took it over.

text: India[edit]

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text: India is one of the world's largest producers of heavy water through its Heavy Water Board and also exports to countries like Republic of Korea and the US. Development of heavy water process in India happened in three phases: The first phase (late 1950s to mid-1980s) was a period of technology development, the second phase was of deployment of technology and process stabilisation (mid-1980s to early 1990s) and third phase saw consolidation and a shift towards improvement in production and energy conservation.

text: Empire of Japan[edit]

text: In the 1930s, it was suspected by the United States and Soviet Union that Austrian chemist Fritz Johann Hansgirg built a pilot plant for the Empire of Japan in Japanese ruled northern Korea to produce heavy water by using a new process he had invented.[51]

text: Norway[edit]

text: In 1934, Norsk Hydro built the first commercial heavy water plant at Vemork, Tinn, with a capacity of 12 tonnes per year.[52] From 1940 and throughout World War II, the plant was under German control and the Allies decided to destroy the plant and its heavy water to inhibit German development of nuclear weapons. In late 1942, a planned raid by British airborne troops failed, both gliders crashing. The raiders were killed in the crash or subsequently executed by the Germans. On the night of 27 February 1943 Operation Gunnerside succeeded. Norwegian commandos and local resistance managed to demolish small, but key parts of the electrolytic cells, dumping the accumulated heavy water down the factory drains.[53]

text: On 16 November 1943, the Allied air forces dropped more than 400 bombs on the site. The Allied air raid prompted the Nazi government to move all available heavy water to Germany for safekeeping. On 20 February 1944, a Norwegian partisan sank the ferry M/F Hydro carrying heavy water across Lake Tinn, at the cost of 14 Norwegian civilian lives, and most of the heavy water was presumably lost. A few of the barrels were only half full, and therefore could float, and may have been salvaged and transported to Germany.

text: Recent investigation of production records at Norsk Hydro and analysis of an intact barrel that was salvaged in 2004 revealed that although the barrels in this shipment contained water of pH 14—indicative of the alkaline electrolytic refinement process—they did not contain high concentrations of D2O.[54] Despite the apparent size of the shipment, the total quantity of pure heavy water was quite small, most barrels only containing 0.5–1% pure heavy water. The Germans would have needed a total of about 5 tons of heavy water to get a nuclear reactor running. The manifest clearly indicated that there was only half a ton of heavy water being transported to Germany. Hydro was carrying far too little heavy water for one reactor, let alone the 10 or more tons needed to make enough plutonium for a nuclear weapon.[54]

text: Israel admitted running the Dimona reactor with Norwegian heavy water sold to it in 1959. Through re-export using Romania and Germany, India probably also used Norwegian heavy water.[55][56]

text: Canada[edit]

text: As part of its contribution to the Manhattan Project, Canada built and operated a 6-tonnes-per-year electrolytic heavy water plant at Trail, British Columbia, which started operation in 1943.

text: The Atomic Energy of Canada Limited (AECL) design of power reactor requires large quantities of heavy water to act as a neutron moderator and coolant. AECL ordered two heavy water plants, which were built and operated in Atlantic Canada at Glace Bay, Nova Scotia (by Deuterium of Canada Limited) and Port Hawkesbury, Nova Scotia (by General Electric Canada). These plants proved to have significant design, construction and production problems. Consequently, AECL built the Bruce Heavy Water Plant (44°11′07″N 81°21′42″W / 44.1854°N 81.3618°W / 44.1854; -81.3618 (Bruce Heavy Water Plant)),[57] which it later sold to Ontario Hydro, to ensure a reliable supply of heavy water for future power plants. The two Nova Scotia plants were shut down in 1985 when their production proved unnecessary.

text: The Bruce Heavy Water Plant (BHWP) in Ontario was the world's largest heavy water production plant with a capacity of 1600 tonnes per year at its peak (800 tonnes per year per full plant, two fully operational plants at its peak). It used the Girdler sulfide process to produce heavy water, and required 340,000 tonnes of feed water to produce one tonne of heavy water. It was part of a complex that included eight CANDU reactors, which provided heat and power for the heavy water plant. The site was located at Douglas Point/Bruce Nuclear Generating Station near Tiverton, Ontario on Lake Huron where it had access to the waters of the Great Lakes.[58]

text: AECL issued the construction contract in 1969 for the first BHWP unit (BHWP A). Commissioning of BHWP A was done by Ontario Hydro from 1971 through 1973, with the plant entering service on June 28, 1973 and design production capacity being achieved in April 1974. Due to the success of BHWP A and the large amount of heavy water that would be required for the large numbers of upcoming planned CANDU nuclear power plant construction projects, Ontario Hydro commissioned three additional heavy water production plants for the Bruce site (BHWP B, C, and D). BHWP B was placed into service in 1979. These first two plants were significantly more efficient than planned, and the number of CANDU construction projects ended up being significantly lower than originally planned, which led to the cancellation of construction on BHWP C & D. In 1984 BHWP A was shut down. By 1993 Ontario Hydro had produced enough heavy water to meet all of its anticipated domestic needs (which were lower than expected due to improved efficiency in the use and recycling of heavy water), so they shut down and demolished half of the capacity of BHWP B. The remaining capacity continued to operate in order to fulfill demand for heavy water exports until it was permanently shut down in 1997, after which the plant was gradually dismantled and the site cleared.[59][60]

text: AECL is currently researching other more efficient and environmentally benign processes for creating heavy water. This is essential for the future of the CANDU reactors since heavy water represents about 15–20% of the total capital cost of each CANDU plant.[60]

text: Iran[edit]

text: Since 1996 a plant for production of heavy water was being constructed at Khondab near Arak.[61] On 26 August 2006, Iranian President Ahmadinejad inaugurated the expansion of the country's heavy-water plant. Iran has indicated that the heavy-water production facility will operate in tandem with a 40 MW research reactor that had a scheduled completion date in 2009.[62][63]

text: Iran produced deuterated solvents in early 2011 for the first time.[64]

text: The core of the IR-40 is supposed to be re-designed based on the nuclear agreement in July 2015.

text: Iran is currently allowed to store only 130 Tons of heavy-water.

text: Pakistan[edit]

text: The 50 MWth heavy water and natural uranium research reactor at Khushab, in Punjab province, is a central element of Pakistan's program for production of plutonium, deuterium and tritium for advanced compact warheads (i.e. thermonuclear weapons). Pakistan succeeded in acquiring a tritium purification and storage plant and deuterium and tritium precursor materials from two German firms.[65]

text: Other countries[edit]

text: Romania produces heavy water at the Drobeta Girdler sulfide plant for domestic and export purposes.[66]

text: France operated a small plant during the 1950s and 1960s.[citation needed]

text: Heavy water exists in elevated concentration in the hypolimnion of Lake Tanganyika in East Africa.[67]  It is likely that similar elevated concentrations exist in lakes with similar limnology, but this is only 4% enrichment (24 vs 28)[68] and surface waters are usually enriched in D2O by evaporation to even greater extend by faster H2O evaporation.

text: Applications[edit]

text: Nuclear magnetic resonance[edit]

text: Deuterium oxide is used in nuclear magnetic resonance spectroscopy when using water as solvent if the nuclide of interest is hydrogen. This is because the signal from light-water (1H2O) solvent molecules interfere with observing the signal from the molecule of interest dissolved in it. Deuterium has a different magnetic moment and therefore does not contribute to the 1H-NMR signal at the hydrogen-1 resonance frequency.

text: For some experiments, it may be desirable to identify the labile hydrogens on a compound, that is hydrogens that can easily exchange away as H+ ions on some positions in a molecule.  With addition of D2O, sometimes referred to as a D2O shake, labile hydrogens exchange away and are substituted by deuterium (2H) atoms. These positions in the molecule then do not appear in the 1H-NMR spectrum.

text: Organic chemistry[edit]

text: Deuterium oxide is often used as the source of deuterium for preparing specifically labelled isotopologues of organic compounds. For example, C-H bonds adjacent to ketonic carbonyl groups can be replaced by C-D bonds, using acid or base catalysis. Trimethylsulfoxonium iodide, made from dimethyl sulfoxide and methyl iodide can be recrystallized from deuterium oxide, and then dissociated to regenerate methyl iodide and dimethyl sulfoxide, both deuterium labelled. In cases where specific double labelling by deuterium and tritium is contemplated, the researcher must be aware that deuterium oxide, depending upon age and origin, can contain some tritium.

text: Fourier transform spectroscopy[edit]

text: Deuterium oxide is often used instead of water when collecting FTIR spectra of proteins in solution. H2O creates a strong band that overlaps with the amide I region of proteins. The band from D2O is shifted away from the amide I region.

text: Neutron moderator[edit]

text:
Heavy water is used in certain types of nuclear reactors, where it acts as a neutron moderator to slow down neutrons so that they are more likely to react with the fissile uranium-235 than with uranium-238, which captures neutrons without fissioning.
The CANDU reactor uses this design. Light water also acts as a moderator,  but because light water absorbs more neutrons than heavy water, reactors using light water for a reactor moderator must use enriched uranium rather than natural uranium, otherwise criticality is impossible. A significant fraction of outdated power reactors, such as the RBMK reactors in the USSR, were constructed using normal water for cooling but graphite as a moderator. However, the danger of graphite in power reactors (graphite fires in part led to the Chernobyl disaster) has led to the discontinuation of graphite in standard reactor designs.

text:
Because they do not require uranium enrichment, heavy water reactors are more of a concern in regards to nuclear proliferation. The breeding and extraction of plutonium can be a relatively rapid and cheap route to building a nuclear weapon, as chemical separation of plutonium from fuel is easier than isotopic separation of U-235 from natural uranium.
Among current and past nuclear weapons states, Israel, India, and North Korea[69] first used plutonium from heavy water moderated reactors burning natural uranium, while China, South Africa and Pakistan first built weapons using highly enriched uranium.

text: In the U.S., however, the first experimental atomic reactor (1942), as well as the Manhattan Project Hanford production reactors that produced the plutonium for the Trinity test and Fat Man bombs, all used pure carbon (graphite) neutron moderators combined with normal water cooling pipes. They functioned with neither enriched uranium nor heavy water. Russian and British plutonium production also used graphite-moderated reactors.

text: There is no evidence that civilian heavy water power reactors—such as the CANDU or Atucha designs—have been used to produce military fissile materials. In nations that do not already possess nuclear weapons, nuclear material at these facilities is under IAEA safeguards to discourage any diversion.

text: Due to its potential for use in nuclear weapons programs, the possession or import/export of large industrial quantities of heavy water are subject to government control in several countries. Suppliers of heavy water and heavy water production technology typically apply IAEA (International Atomic Energy Agency) administered safeguards and material accounting to heavy water. (In Australia, the Nuclear Non-Proliferation (Safeguards) Act 1987.) In the U.S. and Canada, non-industrial quantities of heavy water (i.e., in the gram to kg range) are routinely available without special license through chemical supply dealers and commercial companies such as the world's former major producer Ontario Hydro.

text: Neutrino detector[edit]

text: The Sudbury Neutrino Observatory (SNO) in Sudbury, Ontario uses 1,000 tonnes of heavy water on loan from Atomic Energy of Canada Limited. The neutrino detector is 6,800 feet (2,100 m) underground in a mine, to shield it from muons produced by cosmic rays. SNO was built to answer the question of whether or not electron-type neutrinos produced by fusion in the Sun (the only type the Sun should be producing directly, according to theory) might be able to turn into other types of neutrinos on the way to Earth. SNO detects the Cherenkov radiation in the water from high-energy electrons produced from electron-type neutrinos as they undergo charged current (CC) interactions with neutrons in deuterium, turning them into protons and electrons (however, only the electrons are fast enough to produce Cherenkov radiation for detection). SNO also detects neutrino↔electron scattering (ES) events, where the neutrino transfers energy to the electron, which then proceeds to generate Cherenkov radiation distinguishable from that produced by CC events. The first of these two reactions is produced only by electron-type neutrinos, while the second can be caused by all of the neutrino flavors. The use of deuterium is critical to the SNO function, because all three "flavours" (types) of neutrinos[70] may be detected in a third type of reaction as well, neutrino-disintegration, in which a neutrino of any type (electron, muon, or tau) scatters from a deuterium nucleus (deuteron), transferring enough energy to break up the loosely bound deuteron into a free neutron and proton via a neutral current (NC) interaction. This event is detected when the free neutron is absorbed by 35Cl− present from NaCl deliberately dissolved in the heavy water, causing emission of characteristic capture gamma rays. Thus, in this experiment, heavy water not only provides the transparent medium necessary to produce and visualize Cherenkov radiation, but it also provides deuterium to detect exotic mu type (μ) and tau (τ) neutrinos, as well as a non-absorbent moderator medium to preserve free neutrons from this reaction, until they can be absorbed by an easily detected neutron-activated isotope.

text: Metabolic rate testing in physiology and biology[edit]

text: Heavy water is employed as part of a mixture with H218O for a common and safe test of mean metabolic rate in humans and animals undergoing their normal activities.

text: Tritium production[edit]

text: Tritium is the active substance in self-powered lighting and controlled nuclear fusion, its other uses including autoradiography and radioactive labeling. It is also used in nuclear weapon design for boosted fission weapons and initiators. Some tritium is created in heavy water moderated reactors when deuterium captures a neutron. This reaction has a small cross-section (probability of a single neutron-capture event) and produces only small amounts of tritium, although enough to justify cleaning tritium from the moderator every few years to reduce the environmental risk of tritium escape.

text: Producing a lot of tritium in this way would require reactors with very high neutron fluxes, or with a very high proportion of heavy water to nuclear fuel and very low neutron absorption by other reactor material. The tritium would then have to be recovered by isotope separation from a much larger quantity of deuterium, unlike production from lithium-6 (the present method), where only chemical separation is needed.

text: Deuterium's absorption cross section for thermal neutrons is 0.52 millibarns (5.2 × 10−32 m2; 1 barn = 10−28 m2), while those of oxygen-16 and oxygen-17 are 0.19 and 0.24 millibarns, respectively. 17O makes up 0.038% of natural oxygen, making the overall cross section 0.28 millibarns. Therefore, in D2O with natural oxygen, 21% of neutron captures are on oxygen, rising higher as 17O builds up from neutron capture on 16O. Also, 17O may emit an alpha particle on neutron capture, producing radioactive carbon-14.


document_title: Edward Ferrars

question_text: who does edward marry in sense and sensibility

root

text: Edward Ferrars

text: This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (January 2017) (Learn how and when to remove this template message)

tag: table

text:
Edward Ferrars

Full name
Edward Ferrars

Gender
Male

Age
23

Income
£100/year, after being cut off

Education
privately tutored in the home of the Reverend Mr. Pratt, then at Oxford

Primary residence
Mainly in London with his mother; occasionally at Norland Park; the rest of the time in Oxford

London residence
With his mother

Family

Romantic interest(s)
Miss Lucy Steele, Elinor Dashwood, Miss Morton

Parents
Late Mr. Ferrars, Mrs. Ferrars

Sibling(s)
Fanny Ferrars Dashwood, Robert Ferrars

text: Edward Ferrars is a fictional character in Jane Austen's Sense and Sensibility. He is the elder of Fanny Dashwood's two brothers and forms an attachment to Elinor Dashwood.

tag: p

text: As first described in Sense and Sensibility: "Edward Ferrars was not recommended to their good opinion by any peculiar graces of person or address. He was not handsome, and his manners required intimacy to make them pleasing. He was too diffident to do justice to himself; but when his natural shyness was overcome, his behaviour gave every indication of an open, affectionate heart. His understanding was good, and his education had given it solid improvement. But he was neither fitted by abilities nor disposition to answer the wishes of his mother and sister, who longed to see him distinguished—as—they hardly knew what."

text: His personality, while it lacks the flash of Marianne Dashwood's romantic interest Willoughby, indicates more fortitude. Despite the good common sense that links him to Elinor, he is able to attach himself to other people and form bonds of friendship and love with ease. He exemplifies great loyalty when he sacrifices his potential happiness with Elinor to honor a promise he made to another girl when he was younger. He and Marianne's future husband Colonel Brandon are both models of great character under unimpressive exteriors. This simplicity makes them rather less three-dimensional than Pride and Prejudice's Fitzwilliam Darcy and Emma's Mr. Knightley.

text: He eventually marries Elinor after he is abandoned by Lucy Steele for his now propertied brother.

text: Notable portrayals[edit]

text:
Chet Stratton in 1950
Robin Ellis in 1971
Bosco Hogan in 1981
Hugh Grant in the 1995 film adaptation
Ajith Kumar in the 2000 Tamil adaptation Kandukondain Kandukondain
Dan Stevens in the 2008 BBC serial adaption
Nicholas D'Agosto as "Edward Ferris" in the 2011 film From Prada to Nada
Henry Devas in Helen Edmundson's 2013 BBC Radio 4 adaptation[1]

tag: ul


document_title: Bilbo Baggins

question_text: who played young bilbo in lord of the rings

text: Bilbo Baggins

text: Appearances[edit]

text: The Hobbit[edit]

text: In The Hobbit, Bilbo Baggins, a hobbit in comfortable middle age at 50 years old, was hired as a "burglar," despite his objections, by the wizard Gandalf and 13 Dwarves led by their king Thorin Oakenshield on a quest to reclaim the Lonely Mountain and its treasure from the dragon Smaug. The adventure took Bilbo and the companions through the wilderness, to the elf haven of Rivendell, across the Misty Mountains and the black forest of Mirkwood, to Lake-town in the middle of Long Lake, and eventually to the Mountain itself. Here, after the dragon was killed and the Mountain was reclaimed, the Battle of Five Armies took place.

text: In his journey, Bilbo encountered other fantastic creatures, including trolls, elves, giant spiders, a man who can change shape into a bear, goblins, eagles, wolves and a slimy, murderous creature named Gollum. Underground, near Gollum's lair, Bilbo accidentally found a magic ring of invisibility, which he used to escape from Gollum.

text: By the end of the journey, Bilbo had become wiser and more confident, having saved the day in many precarious situations. Bilbo's journey has been compared to a pilgrimage of grace. The Hobbit can be characterized as a "Christian bildungsroman which equates progress to wisdom gained in the form of a rite of passage.[1] He rescued the dwarves from giant spiders with the magic ring and a short Elven-sword he acquired. He used the ring to sneak around in dangerous places , as well as his wits to smuggle the dwarves out of the elves' prisons. When tensions arose over ownership of the recovered treasure, he tried unsuccessfully to bring the opposing sides to compromise, using the Arkenstone, a stolen heirloom jewel, as leverage. This strained his relationship with Thorin, but the two were reconciled at Thorin's deathbed. At the end of the story, Bilbo returned to his home in the Shire only to find that several of his relatives, believing him to be dead, were trying to claim his home and possessions. In addition to becoming wealthy from his share of the dwarves' treasure, he found that he, like Adam, had traded respectability for experience and wisdom. At the end, Gandalf proclaims Bilbo is no longer the Hobbit he was. This is certainly true as Bilbo has fully matured. Continuing the pilgrimage theme, a true pilgrimage does not end at the destination, but rather when the wanderer is absolved, blessed, and ready to return home.[1]

text: The Lord of the Rings[edit]

text: This Middle-earth-related Section describes a work or element of fiction in a primarily in-universe style. Please help rewrite it to explain the fiction more clearly and provide non-fictional perspective. (October 2016) (Learn how and when to remove this template message)

text: The Fellowship of the Ring, the first volume of The Lord of the Rings, begins with Bilbo's "eleventy-first" (111th) birthday, 60 years after the beginning of The Hobbit. The main character of the novel is Frodo Baggins, Bilbo's cousin,[nb 1] who celebrates his 33rd birthday and legally comes of age on the same day.

text: In T.A. 2989 (S.R. 1389), Bilbo, a lifelong bachelor, adopted Frodo, the orphaned son of his first cousin Primula Brandybuck and his second cousin Drogo Baggins, and made him his heir. Though Frodo was actually "his first and second cousin once removed either way",[2] the two regarded each other as uncle and nephew.

text: All this time Bilbo had kept his magic ring, with no idea of its significance, using it mostly to hide from his obnoxious cousins, the Sackville-Bagginses, when they came to visit. Gandalf's investigations revealed it to be the One Ring forged by the Dark Lord Sauron. The Ring had prolonged Bilbo's life beyond the normal hobbit span, and at 111 he still looked 50. While the Ring did not initially corrupt him as it had its previous owners, it was beginning to affect him; over the years, it had begun to prey on his mind when out of his sight, and he lost sleep and felt "thin, sort of stretched … like butter that has been scraped over too much bread".[2]

text: On the night of his and Frodo's birthday, Bilbo threw himself a party and invited all of the Shire. He signed his home, Bag End, and estate over to Frodo. He then gave a farewell address to his neighbors, at the end of which he put on the Ring and vanished from sight. As Bilbo prepared finally to leave the house, he reacted with panic and suspicion when Gandalf tried to persuade him to leave the Ring with Frodo. Bilbo refused to give up the Ring, referring to it as his "precious" – just as Gollum had. Gandalf lost his temper with his old friend and talked some sense into him. Bilbo admitted he would have liked to be rid of the Ring, and he left it behind, becoming the first person to do so voluntarily. He left the Shire that night, and was never seen in Hobbiton again.

text: His earlier adventure, his eccentric habits as a hobbit, and his sudden disappearance led to the enduring figure of "Mad Baggins" in hobbit folklore, who disappeared with a flash and a bang and returned with gold and jewels.

text: Freed of the Ring's power over his senses, Bilbo travelled first to Rivendell, and then on to visit the dwarves of the Lonely Mountain. After he returned to Rivendell he spent much of the next 17 years living a pleasant life of retirement: eating, sleeping, writing poetry, and working on his memoirs, There and Back Again, known as The Hobbit. He became a scholar of Elven lore, leaving behind the Translations from the Elvish, which forms the basis of what is known to us as The Silmarillion.

text: When Frodo and his friends Samwise Gamgee, Meriadoc Brandybuck and Peregrin Took stopped in Rivendell on their quest to destroy the Ring, Bilbo was still alive but now visibly aged, the years having caught up with him after he surrendered the Ring. Upon seeing the Ring again, he suddenly tried to take it from Frodo; he returned to his senses when a terrified Frodo backed away, and he broke down in tears, apologizing for bringing the burden of the Ring onto Frodo.

text: After the quest to destroy the Ring was fulfilled in The Return of the King, Gandalf and the four Hobbits visited Rivendell on their way back to the Shire and found Bilbo still living there. He gave Frodo a set of manuscripts that later became Translations from the Elvish, and also gave Sam a small bag of gold that represented the last of his share from Smaug's vast hoard. Two years later Bilbo accompanied Gandalf, Elrond, Galadriel, and Frodo to the Grey Havens, there to take ship for Tol Eressëa across the sea, on 29th 'September' T.A. 3021. He had already celebrated his 131st birthday by this time, surpassing the Old Took by one year and becoming the oldest Hobbit ever in Middle-earth. (The natural lifespan of Hobbits is about 100 years.)[3]

text: The Appendices[edit]

text: According to Appendix C of The Lord of the Rings, Bilbo was born to Bungo Baggins and Belladonna Took in T.A. 2890, or S.R. 1290. The Lord of the Rings gives the date of Bilbo's birthday as 22 September,[2] but the actual date in the Shire calendar was Halimath 22; Tolkien tells us in Appendix D that he "used our modern names" for the months "to avoid confusion, while the seasonal implications of our names are more or less the same", so that Halimath is translated as September, but that "the Shire dates were actually in advance of ours by some ten days, and our New Year's Day corresponded more or less to the Shire January 9".[4]

text: The Bagginses of Bag End were one of the oldest, wealthiest, and most respectable Hobbit families in Hobbiton until the year 2941 (SR 1341), when Bilbo inexplicably disappeared on his adventure and was thought dead.

text: Poems and songs written by Bilbo[edit]

text:
"A Walking Song"
"All that is gold does not glitter"
"The Man in the Moon Stayed Up Too Late"
"The Road Goes Ever On"

text: Bilbo's Last Song[edit]

text: Tolkien's posthumously published poem "Bilbo's Last Song", illustrated by Pauline Baynes, describes Bilbo's contemplation of his forthcoming voyage to the Undying Lands. The illustrations evoke his last ride in the company of Elrond from Rivendell to the Grey Havens, as described in The Lord of the Rings.

text: Portrayals in adaptations[edit]

text: In the 1968 BBC Radio serialization of The Hobbit, Bilbo was played by Paul Daneman.

text: Nicol Williamson portrayed Bilbo with a light West Country accent in the 1974 performance released on Argo Records.[5]

text: In the 1977 Rankin/Bass animated version of The Hobbit, Bilbo was voiced by Orson Bean. Bean also voiced both the aged Bilbo and Frodo in the same company's 1980 adaptation of The Return of the King.

text: In Ralph Bakshi's 1978 animated version of The Lord of the Rings, Bilbo was voiced by Norman Bird. Billy Barty was the model for Bilbo, as well as Frodo and Sam, in the live-action recordings Bakshi used for rotoscoping.

text: The 3000th story to be broadcast in the BBC's long-running children's programme Jackanory was The Hobbit, in 1979. Four narrators told the story, with Bilbo's part being played by Bernard Cribbins

text: In the BBC's 1981 radio serialization of The Lord of the Rings, Bilbo is played by John Le Mesurier.

text: In the 1993 television miniseries Hobitit by Finnish broadcaster Yle, Bilbo is portrayed by Martti Suosalo.

text: Throughout the 2003 video game the players control Bilbo, voiced by Michael Beatie. The game follows the plot of the book, but adds the elements of platform gameplay and various side-objectives along the main quests.

text: In The Lord of the Rings Online (2007) Bilbo resides in Rivendell, mostly playing riddle games with the Elf Lindir in the Hall of Fire. The game also includes multiple outlanding[clarification needed] stories about Bilbo's adventures and his ultimate fate from [clarification needed] various Hobbits in the Shire.

text: In Peter Jackson's films The Fellowship of the Ring (2001) and The Return of the King (2003) Bilbo is played by Ian Holm, who had played Frodo in the BBC radio series 20 years earlier. The movies omit the 17-year gap between Bilbo's 111th birthday and Frodo's departure from the Shire, as a result Bilbo mentions in Rivendell that he was unable to revisit the Lonely Mountain before his retirement.

text: In Peter Jackson's The Hobbit film series, a prequel to The Lord of the Rings, the young Bilbo is portrayed by Martin Freeman[6] while Ian Holm reprises his role as an older Bilbo in An Unexpected Journey (2012) and The Battle of the Five Armies (2014).

text: Family tree[edit]

text: This section does not cite any sources. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed. (August 2017) (Learn how and when to remove this template message)

text:
Balbo Baggins

Berylla Boffin

Laura Grubb

Mungo

Pansy

Fastolph Bolger

Ponto

Mimosa Bunce

Lily

Togo Goodbody

Largo

Tanta Hornblower

Bungo

Belladonna Took

Belba

Rudigar Bolger

Longo

Camellia Sackville

Linda

Bodo Proudfoot

Bingo

Chica Chubb

Fosco

Ruby Bolger

Bilbo Baggins

Otho Sackville-Baggins

Lobelia Bracegirdle

Falco Chubb-Baggins

?

Dora

Drogo

Primula Brandybuck

Dudo

?

Lotho

Poppy

Filibert Bolger

Frodo

Daisy

Griffo Boffin

text: Namesakes[edit]

text: The International Astronomical Union names all colles (small hills) on Saturn's moon Titan after characters in Tolkien's work.[7] In 2012, they named a hilly area "Bilbo Colles" after Bilbo Baggins.[8]


document_title: 1793 Philadelphia yellow fever epidemic

question_text: when did the yellow fever epidemic of 1793 start

question_tokens: when did the yellow fever epidemic of 1793 start

text: 1793 Philadelphia yellow fever epidemic

text: Beginnings[edit]

text: In the spring of 1793, French colonial refugees, some with slaves, arrived from Cap Français, Saint-Domingue. The 2,000 immigrants were fleeing the slave revolution in the north of the island.[3] They crowded the port of Philadelphia, where the first yellow fever epidemic in 30 years began in the city in August.[3][4] It is likely that the refugees and ships carried the yellow fever virus and mosquitoes. It is transmitted during mosquito bites. The mosquitoes easily breed in small amounts of standing water. The medical community and others in 1793 did not understand the role of mosquitoes in the transmission of yellow fever and other diseases. Physicians and other survivors of the epidemic wrote extensively about it trying to learn from the crisis.

text: In the ports and coastal areas of the United States, even in the northeast, the months of August and September were considered the "sickly season," when fevers were prevalent. In the South, planters and other people wealthy enough usually left the Low Country during this season. Natives thought that newcomers especially had to undergo a "seasoning" and were more likely to die of what were thought to be seasonal fevers in their early years in the region.[5] Philadelphia then was the temporary capital of the United States, and the government was due to return in the fall. President George Washington left the city.

text: The first two people to die of yellow fever in early August in Philadelphia were both recent immigrants, one from Ireland and the other from Saint-Domingue. Letters describing their cases were published in a pamphlet about a month after they died. The young doctor sent by the Overseers of the Poor to treat the Irish woman was perplexed, and his treatment didn't save her.[6]

text: A 2013 book by Billy G. Smith, professor of history at Montana State University, makes a case that the principal vector of the 1793 plague in Philadelphia (and other Atlantic ports) was the British merchant ship Hankey, which had fled the West African colony of Bolama (an island off West Africa, present day Guinea-Bissau) the previous November, trailing yellow fever at every port of call in the Caribbean and eastern Atlantic seaboard. See: The Ship of Death: The Voyage That Changed the Atlantic World.[7]

text: Epidemic declared[edit]

text: After two weeks and an increasing number of fever cases, Dr. Benjamin Rush, a doctor's apprentice during the city's 1762 yellow fever epidemic, saw the pattern; he recognized that yellow fever had returned. Rush alerted his colleagues and the government that the city faced an epidemic of "highly contagious, as well as mortal... bilious remitting yellow fever."[8] Adding to the alarm was that, unlike with most fevers, the principal victims were not the very young or very old. Many of the early deaths were teenagers and heads of families in the dockside areas.[9] Believing that the refugees from Saint-Domingue were carrying the disease, the city imposed a quarantine of two to three weeks on immigrants and their goods, but was unable to enforce it as the epidemic increased its reach.[10]

text: Then the largest city in the US, with around 50,000 residents, Philadelphia was relatively compact and most houses were within seven blocks of its major port on the Delaware River. Docking facilities extended from Southwark south of the city to Kensington to the north. Cases of fever clustered at first around the Arch Street wharf. Rush blamed "some damaged coffee which putrefied on the wharf near Arch Street" for causing the fevers. Soon cases appeared in Kensington.[11] As the port was critical to the state's economy, the Pennsylvania governor, Thomas Mifflin, had responsibility for its health. He asked the port physician, Dr. James Hutchinson, to assess conditions. The doctor found that 67 of about 400 residents near the Arch Street wharf were sick, but only 12 had "malignant fevers."[12] Alarmed by what Rush and others told him, Mayor Matthew Clarkson asked the city's medical society, the College of Physicians, to meet and advise the city's government and citizens how to proceed.

text: Rush later described some early cases: On August 7, he treated a young man for headaches, fever and vomiting, and on the 15th treated his brother. On the same day a woman he was treating turned yellow. On the 18th a man in the third day of a fever had no pulse, was cold, clammy, and yellow, but he could sit up in his bed. He died a few hours later. On the 19th a woman Rush visited died within hours. Another physician said five persons within sight of her door died. None of those victims was a recent immigrant.[13]

text: The College published a letter in the city's newspapers, written by a committee headed by Rush, suggesting 11 measures to prevent the "progress" of the fever. They warned citizens to avoid fatigue, the hot sun, night air, too much liquor, and anything else that might lower their resistance. Vinegar and camphor in infected rooms "cannot be used too frequently upon handkerchiefs, or in smelling bottles, by persons whose duty calls to visit or attend the sick." They outlined measures for city officials: stopping the tolling of church bells and making burials private; cleaning streets and wharves; exploding gunpowder in the street to increase the amount of oxygen. Everyone should avoid unnecessary contact with the sick.[14] Crews were sent to clean the wharves, streets and the market, which cheered those remaining in the city.[15] Many of those who could left the city.

text: Elizabeth Drinker, a married Quaker woman, kept a journal for years; her account from August 23 through August 30 tells the quickening story of the spread of the disease in the city and the rising toll of deaths. She also describes the many people leaving the city.[16]

text: Temporary hospitals[edit]

text: Like all hospitals of that time, the Pennsylvania Hospital did not admit patients with infectious diseases.

text: The Guardians of the Poor took over Bush Hill, a 150-acre estate farther outside the city, whose owner William Hamilton was in England for an extended stay. Vice President John Adams had recently rented the main house, so yellow fever patients were placed in the outbuildings.[17][18] Nurses were hired to treat patients, under orders by young physicians from the city, who were to visit on a daily basis.

text: The end of August was not traditionally a busy time in the city. Many families who could afford to or who had relatives in the countryside lived elsewhere during that hot month. Beginning in September, shipments generally increased with the arrival of fall goods from Britain. In 1793, the Federal Congress was not scheduled to resume session until November, but the Pennsylvania Assembly met in the first week of September. Founded by the Quaker William Penn, the city was the center of Quaker life in the United States. The Yearly Meeting of the Society of Friends was scheduled to be held in the third week of September.

text: Panic and refugees[edit]

text: Between the College's advisory on August 25 and the death of Dr. Hutchinson from yellow fever on September 7, panic spread throughout the city; more people fled. Between August 1 and September 7, 456 people died in the city. On September 8, 42 deaths were reported.[19] An estimated 20,000 people left the city through September, including national leaders.[10] The daily death toll remained above 30 until October 26. The worst seven-day period was between October 7 and 13, when 711 deaths were reported.[19]

text: Some neighboring towns had patrols on the roads to prevent entry by refugees. The major ports of Baltimore and New York prevented refugees from entering and quarantined them and goods from Philadelphia for weeks.

text: The publisher Mathew Carey published a short pamphlet later in the fall in which he described the changes that had occurred in the life of the city:

text: "Those who ventured abroad, had handkerchiefs or sponges impregnated with vinegar of camphor at their noses, or smelling-bottles full of the thieves’ vinegar. Others carried pieces of tarred rope in their hands or pockets, or camphor bags tied round their necks.... People hastily shifted their course at the sight of a hearse coming towards them. Many never walked on the foot path, but went into the middle of the streets, to avoid being infected in passing by houses wherein people had died. Acquaintances and friends avoided each other in the streets, and only signified their regard by a cold nod. The old custom of shaking hands fell in such general disuse, that many shrunk back with affright at even the offer of a hand. A person with crape [mourning crepe], or any appearance of mourning, was shunned like a viper."[20]

text: Black nurses[edit]

text: The College of Physicians' advisory implied the fever was contagious and people should avoid contact with its victims although "duty" required that they be cared for. Yet in families, when the person with the fever was a mother or father, they could forbid their children from coming near them. Rush knew of Dr. John Lining's observation during the 1742 yellow fever epidemic in Charleston, South Carolina, that African slaves appeared to be affected at rates lower than whites; he thought they had a natural immunity. Writing a short letter to the newspapers under the pseudonym "Anthony Benezet," a Quaker who had provided schooling for blacks, Rush suggested that the city's people of color had immunity and solicited them "to offer your services to attend the sick to help those known in distress."[21][22] Richard Allen and Absalom Jones recalled their reaction to the letter in a memoir they published shortly after the epidemic:

text: Early in September, a solicitation appeared in the public papers, to the people of colour to come forward and assist the distressed, perishing, and neglected sick; with a kind of assurance, that people of our colour were not liable to take the infection. Upon which we and a few others met and consulted how to act on so truly alarming and melancholy occasion. After some conversation, we found a freedom to go forth, confiding in Him who can preserve in the midst of a burning fiery furnace, sensible that it was our duty to do all the good we could to our suffering fellow mortals. We set out to see where we could be useful. The first we visited was a man in Emsley's alley, who was dying, and his wife lay dead at the time in the house, there were none to assist but two poor helpless children. We administered what relief we could, and applied to the overseers of the poor to have the woman buried. We visited upwards of twenty families that day—they were scenes of woe indeed! The Lord was plentiful to strengthen us, and removed all fear from us...[21]

text: In order the better to regulate our conduct, we called on the mayor the next day, to consult with him on how to proceed, so as to be the most useful. The first object he recommended was a strict attention to the sick, and the procuring of nurses. This was attended to by Absalom Jones and William Gray; and, in order that the distressed might know where to apply, the mayor advised that upon application to them they would be supplied. Soon after, the mortality increased, the difficulty of getting a corpse taken away, was such, that few were willing to do it, when offered great rewards. The black people were looked to. We then offered our services in the public papers, by advertising that we would remove the dead and procure nurses. Our services were the production of real sensibility—we sought not fee nor reward, until the increase of the disorder rendered our labour so arduous that we were not adequate to the service we had assumed.[21]

text: Allen noted in his account that because of the increase in mortality, he and Jones had to hire five men to assist them in removing corpses, as most people avoided the sick and the dead.[21] In a September 6 letter to his wife, Rush said that the "African brethren ... furnish nurses to most of my patients."[23] Despite Rush's theory, most of the city's people of color were not immune to the fever. Many of the slaves in Charleston in 1742 could have gained immunity before having been transported from Africa, by having been exposed to yellow fever in a mild case. People who survived one attack gained immunity.[24] A total of 240 blacks died, in proportion to their population at the same rate as whites.[10]

text: Controversy over treatment[edit]

text: Given the limited resources and knowledge of the times, the city's response was creditable. The medical community did not know the natural history of yellow fever, a viral infection spread by the Aedes aegypti mosquito. Efforts to clean the city did not defeat the spread of the fever as the mosquitoes bred in the clean water. Philadelphia's newspapers continued to publish during the epidemic, and through the doctors and others tried to understand and combat the epidemic. On September 7, Dr. Adam Kuhn advised patients to treat symptoms as they arose; he had studied medicine at the University of Uppsala in Sweden.[25]

text: Rush claimed that he tried Kuhn's and Steven's stimulating remedies, and his patients still died. He recommended other treatments, including purging and bloodletting, and published his theories. The hope offered by any of these treatments was soon dashed when it became clear that they did not cure the disease, and the doctors' competing claims demoralized patients.[26]

text: In his 1794 account of the epidemic, Matthew Carey noted that other doctors claimed to have used calomel before Rush and that "its efficacy was great and rescued many from death." Carey added that the "efficacy of bleeding, in all cases not attended with putridity, was great."[27] Rush taught the African-American nurses how to bleed and purge patients. Allen and Jones wrote that they were thankful that "we have been the instruments, in the hand of God, for saving the lives of hundreds of our suffering fellow mortals."[28] Rush's brand of medicine became the standard American treatment for fevers in the 1790s and was widely used for the next 50 years.[29]

text: Rush's claim that his remedies cured 99 out of 100 patients have led historians and modern doctors to ridicule his remedies and approach to medical science. Some contemporaries also attacked him. The newspaper editor William Cobbett attacked Rush's therapies and called him a Sangrado, after a character in Gil Blas, who bled patients to death. In 1799 Rush won a $5,000 libel judgment against Cobbett.[26]

text: Government responses to crisis[edit]

text: The responses of the various levels of government in the city varied. The Federal government had no authority to act and Congress had not been in session since June. President Washington and his cabinet continued to meet until he left the city on September 10 for his scheduled vacation, a period that included laying the cornerstone on September 18 of the new US Capitol to be built in the City of Washington, the designated capital. Employees of the Treasury Department, who collected customs and worked on the country's financial system, worked throughout the epidemic; the post office also stayed open.

text: The state legislature cut short its September session after a dead body was found on the steps of State House. Governor Mifflin became ill and was advised by his doctor to leave. The city's banks remained open. But, banking operations were so slowed by the inability of people to pay off notes because of disruptions from the epidemic that banks automatically renewed notes until the epidemic ended.[30]

text: The mayor Matthew Clarkson organized the city's response to the epidemic. Most of the Common Council members fled, along with 20,000 other residents. People who did not leave Philadelphia before the second week in September could leave the city only with great difficulty, and they faced road blocks, patrols, inspections and quarantines.[31] On September 12, Clarkson summoned fellow citizens interested in helping the Guardians of the Poor. They formed a committee to take over from the Guardians and address the crisis.[32]

text: On the 14th, Clarkson was joined by 26 men, who formed committees to reorganize the fever hospital, arrange visits to the sick, feed those unable to care for themselves, and arrange for wagons to carry the sick to the hospital and the dead to Potter's Field.[32] The Committee acted quickly: after a report of 15-month-old twins being orphaned, two days later the Committee had identified a house for sheltering the growing number of orphans.[33] As noted above, Richard Allen and Absalom Jones offered the services of members of the Free African Society to the Committee.[34]

text: When the Mayor's Committee inspected the Bush Hill fever hospital, they found the nurses unqualified and arrangements chaotic.[35] "The sick, the dying, and the dead were indiscriminately mingled together. The ordure and other evacuations of the sick, were allowed to remain in the most offensive state imaginable... It was, in fact, a great human slaughter-house."[36] On September 15, Peter Helm, a barrel maker, and Stephen Girard, a merchant and shipowner born in France, volunteered to personally manage the hospital and represent the Mayor's Committee.[37]

text: They made rapid improvements in hospital operations: bedsteads were repaired and more brought from the prison so patients would not have to lie on the floor. A barn was adapted as a place for convalescing patients. On September 17, the managers hired 9 female nurses and 10 male attendants, as well as a female matron. They assigned the 14 rooms to separate male and female patients. With the discovery of a spring on the estate, workers were organized to have clean water pumped into the hospital. Helm and Girard informed the Committee that they could accommodate more than the 60 patients then under their care, and soon the hospital had 140 patients.[38]

text: Girard found that the intermittent visits by four young physicians from the city added to the confusion about patient treatment. He hired Jean Deveze, a French doctor with experience treating yellow fever in Saint-Domingue (now Haiti). Deveze cared only for the patients at the hospital, and he was assisted by French apothecaries. Deveze admired Girard's fearlessness in his devotion to the patients. In a memoir published in 1794, Deveze wrote of Girard:

text: I even saw one of the diseased ... [discharge] the contents of his stomach upon [him]. What did Girard do? ... He wiped the patient's cloaths, comforted [him] ... arranged the bed, [and] inspired with courage, by renewing in him the hope that he should recover. —From him he went to another, that vomited offensive matter that would have disheartened any other than this wonderful man.[39]

text: News that patients treated at the hospital were recovering encouraged many people to believe that medicine was gaining control of the fever. But, it soon became clear that mortality at the hospital remained high; about 50% died of those admitted.[40]

text: Reactions by other cities[edit]

text: As the death toll in the city rose, officials in neighboring communities and major port cities such as New York and Baltimore established quarantines for refugees and goods from Philadelphia. New York established a "Committee appointed to prevent the spreading and introduction of infectious diseases in this city", which set up citizen patrols to monitor entry to the city. Stage coaches from Philadelphia were not allowed in many cities. Havre de Grace, Maryland, for example, tried to prevent people from Philadelphia from crossing the Susquehanna River to Maryland.[31][41] Neighboring cities did send food supplies and money; for example, New York City sent $5000 to the Mayor's Committee.[42]

text: Woodbury and Springfield, New Jersey; Chester, Pennsylvania and Elkton, Maryland, were among towns that accepted refugees.[43] President Washington corresponded with members of his cabinet on where to assemble if the epidemic prevented Congress from meeting as scheduled in December. Washington decided to hold the cabinet in early November in Germantown, at that time an independent town ten miles from the heart of Philadelphia.

text: Carey's accusations[edit]

text: In his 1793 account of the epidemic, Mathew Carey contrasted the sacrifices of men like Joseph Inskeep, a Quaker who served on the Mayor's Committee and also visited the sick, with the selfishness of others. When Inskeep contracted the fever, he asked for the assistance of a family whom he had attended when several of its members were sick. They refused; he died, which might have happened even with their aid. Carey reported their refusal.[44]

text: He published rumors of greed, especially by landlords who threw convalescing tenants into the street to gain control of their flats.[45] While he praised Richard Allen and Absalom Jones for their work,[46] he suggested that blacks had caused the epidemic, and that some black nurses had charged high fees and even stolen from those for whom they cared.[47]

text: Allen and Jones quickly wrote a pamphlet to defend the people of color in the crisis. The historian Julie Winch believes they wanted to defend their community, knowing how powerful Carey was, and wanting to maintain the reputation of their people in the aftermath of the epidemic.[46] The men noted that the first nurses from the Free African Society had worked without any pay. As the mortality rate increased, they had to hire men to get anyone to deal with the sick and dying. They recounted that

text: the great prices paid did not escape the observation of that worthy and vigilant magistrate, Matthew Clarkson, mayor of the city, and president of the committee. He sent for us, and requested we would use our influence to lessen the wages of the nurses. But on informing him of the cause, i.e. that of the people over-bidding one another, it was concluded unnecessary to attempt any thing on that head; therefore it was left to the people concerned.

text: Allen and Jones noted that white nurses also profited and stole from their patients. "We know that six pounds was demanded by and paid to a white woman, for putting a corpse into a coffin; and forty dollars was demanded and paid to four white men, for bringing it down the stairs." Many black nurses served without compensation:

text: "A poor black man, named Sampson, went constantly from house to house where distress was, and no assistance, without fee or reward. He was smitten with the disorder, and died. After his death his family were neglected by those he had served. Sarah Bass, a poor black widow, gave all the assistance she could, in several families, for which she did not receive any thing; and when any thing was offered her, she left it to the option of those she served."[48]

text: Response of churches[edit]

text: Church clergy continued to hold services, which helped keep up residents' morale. Rev. J. Henry C. Helmuth, who led the city's German Lutheran congregation, wrote A Short Account of the Yellow Fever in Philadelphia for the Reflecting Christian. He also left a diary. On September 16 he reported that his church was "very full" the day before. In one week in October, 130 members of his congregation were buried. On October 13, he wrote in his diary:

text: Preached to a large gathering about Jes.26,1. I showed that Philadelphia a very blessed city—the Lord is among us and especially in our congregation. I proved this with examples of dead and still living people. Baptized a child. Announced that I could not be with the corpses, that the sick should be reported to me in the morning so that I could visit them in the afternoon.[49]

text: The Yearly Meeting of the Society of Friends at the Arch Street Meeting House drew 100 attendees, most from outside the city. The meetinghouse is not far from the waterfront where the epidemic had started. In their Yearly Epistle following the meeting, the Friends wrote that to have changed the time or place of the meeting would have been a "haughty attempt" to escape "the rod" of God, from which there was no escape.[50] The Quaker John Todd, who attended the meeting, contracted the fever and died of it. His young widow, Dolley Payne Todd, later married James Madison, a Virginia congressman whom she met in Philadelphia and a future U.S. president.[51]

text: End of the epidemic[edit]

text: Doctors, preachers, and laymen all looked to the coming of autumn to end the epidemic. At first they hoped a seasonal "equinoctial gale," or hurricane, common at that time of year, would blow away the fever. Heavy rains in late September seemed to correlate with a higher rate of cases. Residents next anticipated freezing temperatures at night, which they knew were associated with ending fall fevers. By the first two weeks of October and peak of the crisis, gloom pervaded the city. Most churches had stopped holding services, and the post office moved out of the area of the highest number of cases. The market days continued, and bakers continued to make and distribute bread.[52] Several members of the Mayor's Committee died. African-American nurses had also begun dying of the fever. Carts took ill victims to Bush Hill and the dead to burial grounds. Doctors also suffered illness and death, and fewer were available to care for patients. Three of Rush's apprentices and his sister died; he was too sick to leave his house. Such news cast doubts on Rush's methods, but none of those victims had submitted to his harsh treatment.[53]

text: Those refugees from Saint-Domingue who thought they had immunity used the streets freely, but few other residents did. Those who had not escaped the city tried to wait out the epidemic in their homes. When the Mayor's Committee took a quick census of the dead, they found that the majority of victims were poor people, who died in homes located in the alleys, behind the main streets where most of the business of city was conducted.[54]

text: On October 16, after temperatures cooled, a newspaper reported that "the malignant fever has very considerably abated."[55] Stores began to reopen October 25, many families returned, and the wharves were "once more enlivened" as a London-based ship arrived with goods.[56] The Mayor's Committee advised people outside the city to wait another week or 10 days before returning. It published directions for cleaning houses which had been closed up, recommending that they be aired for several days with all windows and doors open. "Burning of nitre will correct the corrupt air which they may contain. Quick lime should be thrown into the privies and the chambers whitewashed." On the 31st, a white flag was hoisted over Bush Hill with the legend, "No More Sick Persons Here."[57]

text: But, after some warm days, fever cases recurred. The white flag had to be struck. Finally on November 13, stagecoaches resumed service to the north and south. A merchant reported that the streets were "in an uproar and rendered the wharves impossible by reason of the vast quantities of wine, sugar, rum, coffee, cotton & c. The porters are quite savvy and demand extravagantly for anything they do."[58] On November 14, the Mayor's Committee recommended purifying houses, clothing and bedding, but said that anyone could come to the city "without danger from the late prevailing disorder."[59]

text: Lists of the dead[edit]

text: An official register of deaths listed 4044 people as dying between August 1 and November 9, 1793 based on grave counts, so the total was probably higher. City officials, medical and religious leaders, and newspaper publishers reported the number and names of victims, based on the minutes of the Mayor's Committee. The Appendix of on-line edition of Minutes lists the names of all the patients admitted to Bush Hill hospital, as well as the disposition of their cases.[60] The publisher Mathew Carey released his history of the epidemic just weeks after its end. He listed the names of the dead at the back of the book, which is one reason it was a bestseller.[61] While Deveze did not reveal his patients' names in describing his treatments, Rush named his patients in his memoir.

text: Controversies over the epidemic[edit]

text: The end of the epidemic did not end the controversies among the city's doctors, who disagreed about causes and treatment. Hearing rumors that colleagues were going to try to get him expelled from the College of Physicians, Rush resigned and formed a new medical society, which many of the city's younger doctors joined.[citation needed] Rush's promotion of his remedies and attacks on others were strongly criticized by the medical community.

text: Cause[edit]

text: Merchants worried more about Rush's theory that the fever arose from the filth of Philadelphia and was not imported from the West Indies. They did not want the port's reputation to suffer permanently. Doctors used his treatments while rejecting his etiology of the disease. Others deprecated his therapies, such as Dr. Deveze, but agreed that the fever had local origins. Deveze had arrived on the refugee ship from Saint-Domingue which many accused of having carried the disease, but he thought it healthy. The doctors did not understand the origin or transmittal of the disease.[62] Historians believe it was brought by refugees from Saint-Domingue, where it was endemic, and transmitted by mosquitoes between the infected and healthy persons.

text: Differing courses of treatment[edit]

text: Dr. Kuhn advised drinking wine, "at first weaker wines, such as claret and Rhenish; if these cannot be had, Lisbon or Madeira diluted with rich lemonade. The quantity is to be determined by the effects it produces and by the state of debility which prevails, guarding against its occasioning or encreasing the heat, restlessness or delirium." He placed "the greatest dependence for the cure to the disease, on throwing cool water twice a day over the naked body. The patient is to be placed in a large empty tub, and two buckets full of water, of the temperature 75 or 80 degrees Fahrenheit's thermometer, according to the state of the atmosphere, are to be thrown on him." The water treatment was also advocated by Dr. Edward Stevens, who in mid-September claimed it had cured Alexander Hamilton, Secretary of the Treasury, of the fever.[63]

text: Rush searched the medical literature for other approaches. Benjamin Franklin had given him letters sent by Dr. John Mitchell, related to treating patients during a 1741 yellow fever outbreak in Virginia. (Franklin never published the letters.) Mitchell noted that the stomach and intestines filled with blood and that these organs had to be emptied at all costs. "On this account," Mitchell argued, "an ill-timed scrupulousness about the weakness of the body is of bad consequences in these urging circumstances.... I can affirm that I have given a purge in this case, when the pulse has been so low that it can hardly be felt, and the debility extreme, yet both one and the other have been restored by it."[64][65]

text: After experimenting, Rush decided that a powder of ten grains of calomel (mercury) and ten grains of the cathartic drug jalap (the poisonous root of a Mexican plant, Ipomoea purga, related to the morning glory, which was dried and powdered before ingesting)[66] would create the desired elimination he was seeking. Since the demand for his services was so great, he had his assistants make as many of his powders in pill form as they could.

text: On September 10, he published a guide to treating the fever: "Dr. Rush's Directions for Curing and Treating the Yellow Fever", outlining a regimen of self-medication. At the first sign of symptoms, "more especially if those symptoms be accompanied by a redness, or faint yellowness in the eyes, and dull or shooting pains about the region of the liver, take one of the powders in a little sugar and water, every six hours, until they produce four or five large evacuations from the bowels..." He urged that the patient stay in bed and "drink plentifully" of barley or chicken water. Then after the "bowels are thoroughly cleaned," it was proper to take 8 to 10 ounces of blood from the arm if, after purging, the pulse was full or tense. To keep the body open he recommended more calomel or small doses of cream of tarter or other salts. If the pulse was weak and low, he recommended camomile or snakeroot as a stimulant, and blisters or blankets soaked in hot vinegar wrapped around the lower limbs. To restore the patient he recommended "gruel, sago, panada, tapioca, tea, coffee, weak chocolate, wine whey, chicken broth, and white meats, according to the weak or active state of the system; the fruits of the season may be eaten with advantage at all times." The sick room should be kept cool and vinegar should be sprinkled around the floor.[67]

text: Rush's therapy was generalized as "purge and bleed," and as long as the patient remained debilitated, Rush urged further purging and bleeding. Not a few of his patients became comatose. The calomel in his pills soon brought on a state of constant salivation, which Rush urged patients to attain to assure a cure. A characteristic sign of death was black vomit, which salivation seemed to ward off.[68] Since he urged purging at the first sign of fever, other doctors began seeing patients who suffered severe abdominal distress. Autopsies after their death revealed stomachs destroyed by such purges.:[69]

text: Unlike other doctors, Deveze did not offer advice in the newspapers during the epidemic. He later discussed treatment in his memoir, which included 18 case studies and descriptions of several autopsies. While he deprecated Rush's harsh purgatives and "heroic" bleeding, he moderately bled patients and also used medicines to evacuate the bowels. Like Rush, he thought poisons had to be "abstracted" in severely debilitated patients. Instead of purges, he used blisters to raise welts on the skin.[70] Unlike Kuhn, he did not favor baths. He preferred to apply heat, using hot bricks on hands or feet. He strongly discounted the traditional treatment for severe fevers, which was to wrap patients in blankets, give them camomile tea or Madeira, and try to bring on sweats.[71] He preferred "acidulated" water to the use of Peruvian bark as many patients found the bark distasteful. He thought the use of opium very helpful.[72]

text: Aftermath[edit]

text: The Governor created a middle path: he ordered the city to be kept clean and the port policed to prevent infected ships, or those from the Caribbean, from docking until they had gone through a period of quarantine. The city suffered yellow fever epidemics in 1797, 1798, and 1799, which kept the origin and treatment controversies alive.[73]

text: Some of the city's clergy suggested the epidemic was a judgment from God.[74] Led by the Quakers, the religious community petitioned the state legislature to prohibit theatrical presentations in the state. Such entertainment had been banned during the Revolution and had only recently been authorized. After an extensive debate in the newspapers, the State Assembly denied the petition.[75]

text: The recurrences of yellow fever kept discussions about causes, treatment and prevention going until the end of decade. Other major ports also had epidemics, beginning with Baltimore in 1794, New York in 1795 and 1798, and Wilmington in 1798, making yellow fever a national crisis. New York doctors finally admitted that they had had an outbreak of yellow fever in 1791 that killed more than 100 people. All the cities that suffered epidemics continued to grow rapidly. The widespread recognition that the epidemics were based along the waterfront meant that cities grew more rapidly in outlying areas, but that was also where land was available at lower cost. Families who could afford it planned to vacate the port cities during the sick season.

text: During the epidemic of 1798, Benjamin Rush commuted daily from a house just outside the city, near what is now 15th and Columbia Streets, to the new city fever hospital, where as chief doctor he treated fever victims.[76] The civic responses to the 1798 epidemics in Philadelphia and New York were more complex than the efforts of the 1793 Mayor's Committee. For instance, Philadelphia forced evacuation of certain neighborhoods and placed refugees in supervised camps. After the epidemic, the city inspected all houses and destroyed those it deemed unhealthy.[citation needed]

text: American doctors did not identify the vector of yellow fever until the late nineteenth century. In 1881 Carlos Finlay, a Cuban doctor, argued that mosquito bites caused yellow fever; he credited Rush's published account of the 1793 epidemic for giving him the idea. He said that Rush had written: "Mosquitoes (the usual attendants of a sickly autumn) were uncommonly numerous..."[77] In the late 1880s, Finlay's theories were confirmed in Cuba by experiments of the US Medical Army Corps under direction of Dr. Walter Reed in the late 1880s, in which subjects allowed themselves to be bitten by infected mosquitoes.

text: In the first week of September 1793, Dr. William Currie published a description of the epidemic and an account of its progress during August. The publisher Mathew Carey had an account of the epidemic for sale in the third week of October, before the epidemic had ended.[78] He accused blacks of causing the epidemic and black nurses of overcharging patients and taking advantage of them. The reverends Richard Allen and Absalom Jones of the Free African Society published their own account rebutting Carey's attacks; by that time Carey had already published the fourth edition of his popular pamphlet.[78] Allen and Jones noted that some blacks had worked for free, that they had died at the same rate as whites from the epidemic, and that some whites had also overcharged for their services.

text: Currie's work was the first of several medical accounts published within a year of the epidemic. Dr. Benjamin Rush published an account more than 300 pages long. Two French doctors, Jean Deveze and Nassy, published shorter accounts. Clergymen also published accounts; the most notable was by the Lutheran minister J. Henry C. Helmuth.[citation needed] In March 1794, the Mayor's Committee published its minutes. (Letters written during the epidemic, which in some cases expressed the last sentiments of victims, were preserved by many families and have been a source for scholars in various archives.)[citation needed]

text: The rapid succession of other yellow fever epidemics in Philadelphia and elsewhere in the northeastern United States engendered many accounts of the efforts to contain, control and cope with the disease. Rush wrote accounts of the 1797, 1798, and 1799 epidemics in Philadelphia. He revised his account of the 1793 epidemic to eliminate reference to the disease being contagious. He varied his cures. In 1798 he was appointed as the chief doctor at the fever hospital. The mortality rate that year was roughly the same as it had been at Bush Hill in 1793, despite radical difference between the therapies used.

text: Noah Webster, then a notable New York newspaper publisher, joined two doctors in publishing the Medical Repository, a magazine that collected accounts of fever epidemics throughout the nation. Webster used this data in his 1798 book, suggesting that the nation was being subjected to a widespread "epidemic constitution" in the atmosphere that might last 50 years and make deadly epidemics almost certain.[79] Yellow fever epidemics became seen as a national crisis. When in 1855 a French doctor published an 813-page history of yellow fever in Philadelphia, covering outbreaks from 1699 to 1854, he devoted only a few pages to the 1793 epidemic.[80]

text: General 20th-century US histories, such as the 10-volume Great Epochs in American History, published in 1912, used short excerpts from Carey's account.[81] The first history of the epidemic to draw on more primary sources was J. H. Powell's Bring Out Your Dead (1949)[citation needed], but he did not use the personal letters, which are largely held by Quaker colleges in the area.[citation needed] While Powell did not write a scholarly history of the epidemic, his work reviewed its historical importance. Since the mid-twentieth century, scholars have studied aspects of the epidemic, first in papers. For example, Martin Pernick's "Politics, Parties, and Pestilence: Epidemic Yellow Fever in Philadelphia and the Rise of the First Party System," developed statistical evidence to show that Republican doctors generally used Rush's therapies and Federalist doctors used Kuhn's.[82]

text: Scholars celebrated the 200th anniversary of the epidemic with the publication of papers on various aspects of the epidemic.[83] A 2004 paper in the Bulletin of the History of Medicine reexamined Rush's use of bleeding.[84]

text: Representation in other media[edit]

text: Several novels have explored the Philadelphia epidemic, including the following:

text:
Charles Brockden Brown, Arthur Mervyn (1799)
Silas Weir Mitchell, The Red City (1909)
Laurie Halse Anderson, Fever 1793 (2000), young adult novel set in Philadelphia

text: The following deals with a 19th-century epidemic of yellow fever in New Orleans:

text: Josh Russell, Yellow Jack, 2000, novel set in New Orleans in the 1840s before the Civil War


document_title: List of wine-producing countries

question_text: who makes the most wine in the world

question_tokens: who makes the most wine in the world

text: List of wine-producing countries

text: The following is a list of the top wine-producing countries and their volume of wine production for the year 2014 in metric tonnes, according to the Food and Agriculture Organization (FAO), which is an agency of the United Nations; this is the latest information available from the FAO.

text: Their data show a total worldwide production of 31 million tonnes (1,000 kg) of wine (which roughly corresponds to 1,000 l) with the top 15 producing countries accounting for over 90% of the total.[1]

text:
Wine production by country in 2014

Rank
Country
(with link to wine article)
Production
(tonnes)

1
 Italy
4,796,600

2
 Spain
4,607,850

3
 France
4,293,466

4
 United States
3,300,000

5
 China
1,700,000

6
 Argentina
1,498,380

7
 Chile
1,214,000

8
 Australia
1,186,343

9
 South Africa
1,146,006

10
 Germany
920,200

11
 Portugal
603,327

12
 Romania
378,283

13
 Greece
334,300

14
 Russia
327,400

15
 New Zealand
320,400

16
 Brazil
273,100

17
 Hungary
258,520

18
 Austria
199,869

19
 Serbia
198,183

20
 Moldova
149,850

21
 Bulgaria
130,500

22
 Georgia
108,600

23
 Switzerland
93,365

24
 Ukraine
86,904

25
 Japan
85,000

26
 Peru
73,000

27
 Uruguay
72,500

28
 Canada
54,663

29
 Algeria
52,000

30
 Czech Republic
52,000

31
 Macedonia
51,013

32
 Croatia
45,272

33
 Turkey
44,707

34
 Mexico
39,360

35
 Turkmenistan
39,000

36
 Morocco
37,000

37
 Uzbekistan
36,000

38
 Slovakia
32,527

39
 Belarus
29,980

40
 Kazakhstan
21,993

41
 Tunisia
21,500

42
 Albania
24,000

43
 Montenegro
16,000

44
 Lebanon
14,700

45
 Slovenia
13,229

46
 Colombia
13,000

47
 Luxembourg
12,494

48
 Cuba
12,080

49
 Estonia
11,104

50
 Cyprus
10,302

51
 Azerbaijan
9,512

52
 Bolivia
9,422

53
 Madagascar
8,350

54
 Bosnia and Herzegovina
7,524

55
 Armenia
6,174

56
 Lithuania
6,005

57
 Egypt
5,000

58
 Israel
5,000

59
 Belgium
2,900

60
 Latvia
2,450

61
 Malta
2,426

62
 Zimbabwe
1,750

63
 Kyrgyzstan
1,700

64
 Paraguay
1,500

65
 Ethiopia
1,297

66
 Jordan
550

67
 United Kingdom
425

68
 Panama
159

69
 Tajikistan
150

70
 Liechtenstein
79

71
 Syria
70

72
 Reunion
30