Réaumur, Ren

views updated

RéAUMUR, RENé-ANTOINE FERCHAULT DE

(b. La Rochelle, France, 28 February 1683; d. near St-Julien-du-Terroux, France, 18 October 1757)

mathematics, technology, natural history, biology, experimental physics.

Réaumur was of an illustrious Vendee family, the Ferchaults, who prospered in trade and purchased the ancient Réaumur estate in the early seventeenth century. Through a protracted lawsuit Réaumur’s grandfather, Jean Ferchault, obtained half the seignorial rights over his newly acquired fiefdom and thus entered into ranks of the lesser French nobility. René Ferchault, Reamur’s father, was a conseiller au présidial at La Rochelle, a position corresponding to an appellate judge in an intermediate provincial court. He municipal magistrate from Calais, in April 1682; René-Antoine was born the following February. Réaumur’s father dies nineteen months later. A second son, Jean-Honoré, was born posthumously. Reamur and his brother were reared by their mother with the aid of several aunts and uncles.

Concerning Réaumur’s early education, nothing is known with certainty. Probably he studies with either the Oratorians or the Jesuits at La Rochelle. Then, in accordance with established custom among the bourgeoisie and lesser nobility of the region, he would most likely have been sent to study with the Jesuits at Poitiers. In any case, Réaumur’s early education probably included very little physics or mathematics. In 1699 his uncle, Gabriel Bouchel, summoned him to Bourges to study law. He went there with his younger brother and stayed for three years.

In 1703 Réaumur went to live in Paris, where he met a cousin on his mother’s side, Jean-Francois Henault, the future Président.1 Henault was studying mathematics with a certain M. Guisnée, an obscure “student geometer” of the Academy of Sciences.2 Réaumur decided to take lessons from Guisnee and, according to Henault, after only three sessions knew more than his cousin and as much as his instructor. It was probably through Guisnée that Réaumur became acquainted with the great mathematician Pierre Varignon. Varignon became Réaumur’s friend, teacher, and guide; and in March 1708 he nominated him to be his “student geometer” at the Academy of Sciences.

Réaumur’s first three communications to the Academy, on geometrical subjects, were presented in 1708 and 1709, and demonstrate a degree of mathematical sophistication worthy of a student of Varignon. Had Réaumur decided to remain a mathematician, he might well have been one of the greatest geometers of his age. In November 1709, however, he quite suddenly changed the course of his scientific career by reading a paper on the growth of animal shells. From then on, Réaumur’s work would be characterized by its extraordinary richness and diversity, but never again would he devote himself to the pure mathematical researches that had so fascinated him in his youth.

Technology and Instrumentation . Shortly after the formation of the Paris Academy of Sciences, Louis XIV’s finance minister, Colbert, charged it with the task of collecting description of all the arts, industries, and professions. This work was intended to be a sort of industrial encyclopedia which was to present the secret processes of industrial technology so that they might be better examined and improved. The French Academy, unlike the Englishy Royal Society, was an integral part of the French bureaucratic system. This governmental role of the Academy became more and more pronounced throughout the eighteenth century as academicians assumed administrative control of French technology as constultants, inspectors, and even directors of industry.3 Réaumur was one of the earliest and most enthusiastic supporters of this technocratic function of the Acadymy, and perhaps it was for this reason that he was given charge of writing the vast industrial encyclopedia that Colbert had projected.

Réaummur began this enormous task in 1713 with his “Description de l’art du tireur d’or,” a paper on the art of drawing gold into thread and wire. Two years later he published his investigations of the arts dealing with precious stones, in which he showed that certain turquoise stones were actually fossilized animal teeth. His most significant and original contribution to industrial technology was unquestionably his investigation of the iron and steel industry, the results of which he presented in a series of memoris read before the Academy in 1720, 1721, and 1722.4 Réaumur was not a trained engineer or metallurgist and knew only a little chemistry; but he did bring to these researches a profound mathematical ability, an extraordinarily keen power of observation, a lively experimental imagination, and a fine rational intellect.

The French government, especially the regent, Philippe II, duke of Orleans, took great interest in Reamur’s work. It was primarily through the duke’s good offices that Réaumur was able to obtain documentation concerning the iron and steel industries of foreign countries. The regent also subsidized Réaumur’s researches by granting him a pension of 12,000 livres on the postal farm. All this generosity was based on the mercantilistic policy of the French government, which encouraged and subsidized native industries in hopes of improving the balance of trade. The French ferrous metals industry was technologically backward, and it was hoped that Réaumur’s study would help to remedy the situation.

The first part of Réaumur’s investigation concerns the production of steel. This was usually accomplished in the eighteenth century by the lengthy and expensive process of cementation. Small pieces of wrought iron were mixed with charcoal and heated for two or three weeks, until the iron was carburized or case-hardened into blister steel. In the first part of his study, Réaumur was concerned to find the best possible cement, that is, the best combination of substances to mix with the iron. His procedure was experimental and crudely empirical, although of course he knew from the experience of generations of ironmasters what kinds of substances to try. He made dozens of tiny, earthen crucibles of equal size and shape and capable of holding about half a pound of iron. This way he could make about forty trials at once in the ovens that were available to him. The experiments were rigidly controlled in such a way as to insure that the only variable would be the cement. After innumerable experiments of this nature, Réaumur concluded that the best mixture was a specific combination of chimney soot, charcoal, ashes, and common salt.

This result, however, is less significant than Réaumur’s conclusion concerning the nature of steel. He recognized that steel, far from being a more refined form of iron, as most people thought, was in fact impure iron the small parts of which were interpenetrated with “sulfurous and saline particles.” Réaumur is sometimes taken to task for not having recognized that steel is iron combined with a small quantity of carbon; but given the relatively primitive state of early eighteenth-century chemistry, he could hardly have reached such a conclusion. Also, it should be remembered that the “sulfurous particles” he believed to be one of the constituents of steel were not particles of common sulfur. In the parlance of eighteenth-century chemistry, the term “sulfurous” usually referred to an inflammable or oily principle that was present in combustible bodies, such as charcoal, chimney soot, and other carboniferous substances. Thus Réaumur was closer to realizing the truth about the nature of steel than many people give him credit for.

Réaumur also investigated the treatment of steel after it was manufactured. He was especially interested in the tempering process, for which he attempted, without much success, to give a scientific explanation. He also noted that by rupturing a steel sample and examining the texture of the grain at the point of breakage, one could determine the quality of the steel. The better to determine the relative hardness of metals, Réaumur set up a scale of seven substances not unlike the hardness scale contrived by Mohs a century later and still in use by mineralogists. He also invented an apparatus for measuring the flexibility of tempered steel wire.

The second part of Réaumur’s study concerns his attempts to produce a malleable (nonbrittle) cast iron. In the eighteenth century cast iron was made by heating iron ore in a blast furnace at temperatures high enough to produce the metal in a molten state. The resulting iron always had a high carbon content, which had the advantage of lowering its melting point and thus making it suitable for casting, but the disadvantage of making it brittle and thus unsuitable for objects that had to withstand severe strain. Guns were often cast of iron instead of the preferred bronze; but they were liable to fracture and explode, causing more deaths among the friends at the firing end than among the enemies at the receiving end. It was of the greatest importance, not only to the art of war but also to the arts of peace, that a cast iron be produced that had the strength of steel and the resilience of bronze. This was the ultimate goal of Réaumur’s entire study.

Although the composition of cast iron is fairly complex and the chemical tools available to Réaumur were quite primitive, he nonetheless came surprisingly close to identifying its true nature. Just as steel is made harder and more brittle than iron by the penetration between its parts of sulfurous and saline particles, so, Réaumur thought, cast iron is made harder and more brittle than steel by the interpenetration of its parts by still more sulfurous and saline particles. If one substitutes “carbon” for “sulfurous and saline particles,” then one has the modern notion of what constitutes the basic differences between wrought iron, steel, and cast iron.

To remove the brittleness of cast iron, Réaumur reasoned, it was necessary to remove at least some of the sulfurous and saline particles. Heat would open the pores of the metal and force out many of the offending particles; but it was necessary to find a substance that would combine with them, thus preventing their reentry into the body of the metal. Again Réaumur’s method for finding the best substance to achieve this end was largely inspired guesswork. At first he tried bone ash and powdered chalk, but the results were not entirely satisfactory.

He then turned his attention to an interesting substance that had appeared as a by-product of some of his experiments. He had noticed that when cast iron plaques were heated in his oven for several days, a thick layer of reddish powder formed on them. This substance was known to chemists as “saffron of Mars,” and it was believed to be a calcined or burned iron. Réaumur reasoned that iron in this state was divested by fire of all its oily, sulfurous, and saline particles, and that therefore it would be a substance most fit to reabsorb those same particles, like a chemical sponge. He entirely surrounded pieces of cast iron with this powder, placed the mixture in a crucible, and heated it to bright red. After several days Réaumur discovered that the iron had become soft, resilient, and malleable, rather like wrought iron. Unwittingly, he had found the process for making European malleable castings or “whiteheart.” Unfortunately for the French iron industry, Réaumur did not fully realize the importance of this discovery, and did not emphasize it sufficiently. The reason seems to be that he thought that the saffron of Mars (the red oxide of iron) was a particular substance obtained only through the firing of manufactured iron and that it was, therefore, quite uncommon, relatively expensive to produce, and thus unsuitable for large-scale enterprise. In fact it is, as we now know, the same substance as the common and inexpensive red ore of iron. Of so little importance did Réaumur consider this process that when he returned to the subject in his Nouvel art d’adoucir le fer fondu (1726), he neglected altogether to mention it. Only in the nineteenth century was the “Réaumur process” exploited on a large commercial scale.

Réaumur also studied and worked in the tinplate industry. Once encouraged and subsidized by the government, the French tinplate industry had fallen into a state of utter ruin during the early part of the eighteenth century. At the public assembly of the Academy of Sciences on 11 April 1725, Réaumur delivered a paper in which he revealed the basic industrial secrets of tin-plating. It was believed that once the essential processes of the industry became known, anyone possessing the necessary capital could set up a tinplate factory in France. Indeed, Réaumur helped to found such an operation at Cosne-sur-Loire; but the costs of production proved too great to meet competition from imported German tinplate.

From about 1717 Réaumur undertook a lengthy and intensive investigation of the porcelain industry. China porcelain was in great demand in Europe because of its delicate beauty and its soft, appealing translucence. European workmen had attempted to imitate it, but they were deceived by its vitrified texture into believing that common glass entered into its composition. In France factories were set up at Rouen (1673) and St. Cloud (1677) to manufacture an artificial porcelain made with a previously fired glassy mixture or frit of the type known as soft paste (păte tendre) to distinguish it from hard paste, from which true porcelain is made. In Germany a technique for making true, hard-paste porcelain was discovered by Johann Friederich Böttger in association with Tschirnhauscn; and as early as 1708 their factory at Dresden began to turn out a hard, red stoneware in almost every way comparable with a type of true china.

What seems to have initiated Réaumur’s interest in porcelain was a letter published in 1717, from a Jesuit missionary to China, Father Francois-Xavier Entrecolles, in which he described in detail the processes used to manufacture porcelain in the famous Chinese factory at Ching-te-chen (Fou-liang). Along with his letter Father Entrecolles sent samples of the two substances used in the making of china, One of these substances, petuntse, was a feldspar; the other, kaolin, was a clay. Réaumur obtained the samples from Entrecolles’s correspondent and began a two-year effort to identify them. The regent ordered intendants all over France to send specimens of all manner of sands, stones, earths, and other mineral substances found in their districts. Although large numbers of samples were collected, Réaumur was not able to identify the two Chinese specimens or to find their French equivalents.

Réaumur did, however, discover and make public, in a series of memoirs delivered before the Academy of Sciences, the secret processes for making soft-paste porcelain from glass. He confirmed by experiment that, despite their similar appearances, true China porcelain and the French imitation were quite differently composed. During the course of his experiments Réaumur invented a new type of crystalline ceramic that has proved useful in the twentieth century in protecting rocket nose cones from overheating.

Although Réaumur was unsuccessful in his attempts to discover the secret of making hard-paste porcelain, he did prepare the way for later investigators. His pupil Jean-Etienne Guettard discovered French sources of the two substances, kaolin and petuntse, necessary for the manufacture of porcelain. Later chemists and academicians, such as Pierre-Joseph Macquer, Jean Hellot, and the count of Milly, built on his pioneer researches a complete and detailed technological structure that was to make French porcelain among the finest in the world.

Réaumur was perhaps best known for the thermometer scale that he invented and that bears his name. Thermometers had been in use for about a century when he became interested in them, but there were not yet any universally accepted scales that would allow scientists who were not in the same place to compare their thermometric findings. Fahrenheit’s scale was beginning to be adopted both in England and in Holland; but with its two fixed points and its scale divided linearly into a given number of degrees, it was accurate only if the inside diameter of the hollow thermometer tube was perfectly regular.

Réaumur sought to avoid this difficulty by constructing a thermometer with a single fixed point and a degree defined volumetrically (instead of linearly) in terms of some fraction of the total volume of liquid in the thermometer bulb. To fashion his thermometer according to these principles, he made a series of pipettes, the smallest equal to the volume of a single degree and the others equal to 25, 50, or 100 times the volume of the smallest. Then, using these pipettes, he filled a thermometer with 1,000 measures of liquid. Since it was not necessary to use the thermometric liquid itself when graduating the thermometer, Réaumur first used water and then switched to mercury, which he found more convenient. The place on the thermometer tube reached by 1,000 measures of liquid was marked 0°, and each degree above and below that single and arbitrary fixed point was equal to 1/1,000 the volume of the liquid at 0°. Then the graduated thermometer was emptied and refilled to a point just below the 0° mark with the thermometric liquid—in this case alcohol. The thermometer was then placed in ice water and alcohol was carefully added until it reached the 0° mark. Then the tube was hermetically sealed.

The one serious drawback to Réaumur’s thermometer was that different strengths of alcohol have different coefficients of dilation, so that while one type of alcohol might expand one degree after the application of a certain amount of heat, another might expand two degrees under the same conditions. It was vital that all thermometers scaled according to his system have the same grade of alcohol. Réaumur suggested that the alcohol used in his thermometers be of a type that would dilate 80 degrees—that is, 8 parts in 100—between the temperature of ice and the temperature at which the alcohol began to boil in an open thermometer tube. Owing to an unfortunate confusion of language in his article on the thermometer, however, nearly everyone believed that 80° on his scale was the temperature of boiling water; and as a result, when so-called Reaumer thermometers began to be made by the artisans of Paris, they were nearly all scaled linearly with respect to two fiducial points, 0° for ice and 80° for boiling water. Scientists using mercury for their thermometers and basing their degree on the same value as Réaumur (1/1,000 the volume of the liquid at 0°) found the boilding point somewhere between 100° and 110°. In short, while there were many types of thermometers named for Reaumer, few were constructed in accordance with his specific instructions. As a result, it is often imposible to tell from the text of an eighteenth-century author claiming to use a Réaumur thermometer exactly what scale he is referring to, unless he happens to mention a universal fixed point, such as the temperature of boiling water.

Natural History. Réaumur was among the greatest naturalists of his or any age. In the breadth and range of his researches, in the patient detail of his observations, and in the brilliant ingenuity of his experiments, it would be difficult to name his equal. Thomas Henry Huxley has compared his favourably with Darwin.5

Réaumur’s motives in pursuing natural history were a strange mixture of hardheaded practicality and frivolous delight in the curiosities of nature. In 1715 his investigation of artifical pearls led him to study the substance that gave luster to the scales of fishes. These researches were in turn linked to inquiries that he had undertaken since 1709 into the formation of mollusk shells, which he showed to grow by the addition of successive layers rather than by the incorporation of new matter into an already existing structure. In 1717 he attempted artifically to stimulate pearl formation in bivalves, and in 1711 he rediscovered the secret of making the purple dye of the ancient Romans from the substance produced by a particular species of mollusk. Réaumur also investigated the means by which mollusks, starfish, and various other invertebrates move about. He was the first to describe ambulacral feet. In 1710 he published a memoir on the fabric he had made from spiders’s silk. He presented the duke of Noailles with a pair of spiders’ silk stockings, and he gave Jean-Paul Bignon some Spiders’ silk gloves. His memoir on spiders’ silk was translated into Italian, English (it was inserted into the Philosophical Transactions of the Royal Society ), and Chinese (by request of the Manchu emperor).

Réaumur’s greatest work in natural history was his Memoires pour servir a l’histoire des insectes, published in six volumes between 1734 and 1742. He had originally intended to published during his lifetime, nothing remained of the project but fragments in manuscript, some of which were not published until the twentieth century.6 It is not altogether clear why Réaumur stopped writing his great work at such an early date. there is some evidence, however, that he may have been discouraged by the jealous rivalry with his younger and more popular contemporary Buffon.7

The term “insect” was used in the early eighteenth century to designate almost any small invertebrate—not just hexapods or six-legged arthropods. The word refers primarily to creatures possesing segmented bodies; thus spiders, myriopods, and worms were usually included in the class. Réaumur’s concept of the insects was even broader; he included polyps, mollusks, crustaceans, and even reptiles and amphibians. “The crocodile is certainly a fierce insect,” he once proclaimed, “but I am not in the least disturbed about calling it one.”8

Because of their large numbers and great diversity, insects were difficult to classify. Taxonomical schemata had been formulated by Aldrovandi and Vallisnieri which relied on superficial physiological and ethological, as well as morphological, characteristics. Swammerdam made things even more complicated by taking into consideration developmental characteristics. It is typical of Réaumur’s approach that he tended to neglect morphology (which has since been used as the basis for insect classification) and concentrated instead on ethological characteristics. As a result, it is difficult at times to determine exactly what insect he was discussing. He seemed fascinated above all with insect behavior, obviously admiring the industry, diligence, ingenuity, organization, and skill of those small creatures. There is something almost of the eighteenth-century bon bourgeois in this description of the bees and the ants; and just as middle-calss humans are categorized according to their professions, so, Réaumur thought, the insects might be classified according to their industries and occupations:

… the portion of the history of insects to which I am most sensitive is that which concerns their ingenuity [génie],9 their industries; also their industries will often decide the order in which 1 shall treat them. I have thought, for example, that one would prefer to see together all the insects that know how to clothe themselves, and which are above all remarkable for that, than to find them dispersed in different classes as they necessarily would be according to the methods of Swammerdam and Valisnieri.10

Another characteristic of Réaumur’s approach to the natural history of insects is his persistent utilitarianism. There is in him little of the gimcrack virtuosity which seeks to know petty and useless details merely for the sake of knowing them. He doubtless admired the cunning practicality of the insects because it reflected his own turn of mind. He sought always to justify his researches by emphasizing their usefulness. Near the beginning of the first volume of his monumental study on insects he discussed at some length the economic value of entomological research. Silk, wax, honey, lacquer, and cochineal, to name just a few, are products of economic importance derived from the “industries” of insects.11 Réaumur apparently believed that it might be possible to derive useful technological procedures from the observation of insect activities. He sought, for example, to mimic the industry of the bees by attempting to make wax from pollen.12 He seemed to imply that perhaps the caterpillars and the spiders have something to teach us about weaving, that perhaps the useful resins manufactured by the ants could be made artificially.

The study of insects is profitable from another point of view as well—pest control. As early as 1728, Réaumur had investigated the life cycle of clothes moths in order to determine the best means of eradicating them. Again, at the beginning of his first volume on the natural history of insects he stressed the utility of this aspect of his research.

An infinity of these tiny animals defoliate our plants, our trees, our fruits…. they attack our houses, our fabrics, our furniture, our clothing, our furs. … He who in studying all the different species of insects that are injurious to us, would seek means of preventing them from harming us, would seek to cause them to perish, to cause their eggs to perish, proposes for his goal important tasks indeed.13

Réaumur, in short, was a pioneer in applied entomological research.

The most widely read portion of Réaumur’s natural history of insects is probably the nine memoirs of volume V on the history of the bees. Réaumur lavished an enormous amount of time and observational and experimental skill on these productive social insects. His descriptions were minute and exacting in every detail, and his experiments were among the most ingenious he ever contrived. Réaumur was one of the first to undertake extensive quantitative research on insects. He discovered that by immersing a hive in cold water he could, in effect, anesthetize the insects for a time, thus enabling him to separate the members of the bee community into their various classes and to count them. He carefully kept track of the number of bees leaving the hive in the course of a day, measured the average amount of pollen brought back by each, and from this estimated the weight of a single day’s harvest. Réaumur also counted cells and larvae in a hive relative to its adult population; estimated the prodigious number of eggs laid by a single queen; weighed a swarm of bees in order to determine their number; measured the temperature of the hive and kept track of its variations in relation to both the season and the number and density of its inhabitants; and even made very careful investigations of the geometric form of the honey cells.

With regard to the position and function of the queen in bee society, Réaumur’s researches were extensive and original. He discovered that all hives, even those very close to swarming, have only one queen; if others are introduced, they will be rejected or even killed. He found that if a colony is deprived of its queen, it must make a new one (by feeding a special substance called royal jelly to a developing larva) or it will die. He discovered that a hive without a queen will (under certain conditions) accept an exogenous ruler.

Réaumur kept track of individual bees by tinting them with various dyes. He dissected bees and their larvae and had detailed plates made to accompany his treatise. He made some of the first tentative studies of communication among the bees. In short, there was no aspect of the life cycle or behavior of bees too minute or too unimportant to escape his attention. He took every pain, every precaution to make his study as complete and exhaustive as possible. And so it was with the other insects he studied.

Biology and Genetics. Réaumur’s biological and genetical notions were dominated by the ideas of the preformationists. Given the prevalence of the mechanical philosophy at the beginning of the eighteenth century, it was very difficult to imagine ways in which new biological forms could arise from undifferentiated matter. To deal with this problem, the preformationists went so far as to deny that there had ever been generation of any kind, whether of biological individuals or of members or parts. Thus when Leeuwenhoek peered through his microscope at semen, he fancied that he observed a tiny fetus encased in the head of each sperm. When properly “planted” in the female womb, these tiny creatures would simply enlarge into infants. Swammerdam believed that each structure of the adult butterfly was present in the infant caterpillar. All that was needed to change the latter into the former was that the caterpillar slough off its skin and allow the preexisting butterfly parts to unfold and grow. There was neither metamorphosis nor generation, only unfolding and growth. It follows, then, that every living creature that ever will exist actually exists now, with all its mature parts, in seeds or in seeds of seeds. The unborn are indescribably small, but they are nonetheless there, even though we may not be able to see them. In the biology of the preformationists there was literally nothing new under the sun and Adam was, in the realest of senses, the father of us all, or perhaps (because eighteenth-century opinion was divided on the matter) Eve was the universal mother.

Réaumur gave his cautious support to some of the ideas of the preformationists, largely because the alternative—the outmoded Aristotelian notions of epigenesis—seemed, in an era insistent upon mechanism, absurd and without foundation. For example, in his discussion of caterpillars and butterflies, which takes up takes up the first two volumes of his natural history of the insects, Réaumur repeated Swammerdam’s observations on the development of the chrysalis and came to the same conclusion—the parts of the adult butterfly are simply enlargements of structures pre-existent beneath the skin of the caterpillar. It is indicative of the power of these preformationist conceptions that when he was unable to find certain preexistent structures in the caterpillar, he asserted that they were there nonetheless, although invisible.

Others of Réaumur’s observations lent support to the ideas of preformation. For example, he discovered that different degrees of heat could retard or accelerate the growth of the butterfly chrysalis. This experiment showed that conditions in the environment played an important role in the rate of biological development. The implication was that preformed biological structures could, like the chrysalis, remain in a state of suspended animation until the conditions became suitable for their development.

Another observation that seemed to lend credence to preformationism was the discovery of parthenogenesis among the aphids. It had been noticed long before that female aphids seemed capable of producing abundant offspring even when there were no males around to fertilize them. Furthermore, no one had ever observed aphids in the act of mating. Réaumur suggested that one could discover whether it was possible for aphids to reproduce without sexual contact by raising them in isolation from the time of their birth. He attempted the experiment himself, but his aphids died before reaching sexual maturity. His student, the young Genevan naturalist Charles Bonnet, repeated the experiment at Réaumur’s suggestion and succeeded in producing aphids parthenogenetically. To Bonnet the experiment seemed to show that the preformed fetus was in the female egg rather than in the male sperm, and he became a leader of the “ovist” school of preformationism.

Réaumur never accepted all the ideas of preformationism, for he was too aware of the difficulties some aspects of the theory entrained. How can it be, for example, that offspring resemble both of their parents, since the preformed infant would have to originate in the seed of only one of them? In the second edition of his study of the technique of artificial incubation, Réaumur included an account of the inheritance of human Polydactyly showing that the trait is passed to the offspring through male and female parents alike. It was precisely this kind of observation of biparental inheritance that led many biologists in the middle of the eighteenth century to abandon the notions of preformationism altogether and adopt pangenetic theories instead.

As early as 1712, Rdaumur had apparently rejected the idea of emboîtement (the “encasement” of germs within germs). In that year he published a paper in which he demonstrated that certain crustaceans had the power to regenerate missing legs or parts of legs lost through misadventure. A preformationist account of this type of regeneration posed serious difficulties. Presumably any given place on the leg would have to possess a germ containing a preformed leg or a preformed section of leg similar to the section below the place where the germ was located. Furthermore, to account for secondary regenerations, one would have to assume that each of these tiny preformed legs contained multitudes of yet tinier preformed legs and sections of legs, and so on ad infinitum. Yet if the germs were not preformed, where did they come from? Were they, then, truly generated from undifferentiated matter? Réaumur was at a loss to explain the phenomenon. The preformationist account of regeneration was manifestly absurd; but then, so it seemed, were the alternative explanations.

If the discovery of regenerated animal members posed serious difficulties for preformationism, the discovery of regeneration in the fresh-water hydra nearly devastated the theory and many others as well. It was a cousin of Charles Bonnet, Abraham Trembley, who collected some of these tiny creatures from a stagnant pool in the summer of 1740 and observed that they had animal like powers of locomotion, extension, and contraction. Uncertain whether to classify them as animals or plants, he communicated his findings to Réaumur and asked for his opinion. After observing the creatures, Réaumur was convinced that they were indeed animals. Trembley had also cut one of his “polyps,” as they were to be called, transversely in two and noted, to his great astonishment, that each part continued to manifest signs of life and that at the end of about nine days each had regenerated its other half. Later it was found that one could divide hydras into almost as many pieces as one pleased and each part would live independently and, after a time, regenerate the whole. It was Réaumur who announced these remarkable facts to a startled and somewhat incredulous scientific community in March and April 1741. The following summer his student Guettard went to the coast to test the regenerative powers of several marine animals.

The discovery of the hydra and its peculiar ability to sustain life even when divided into a number of small parts caused a profound shock among European naturalists. The observation of analogous regenerative powers in starfish, sea anemones, and worms was likewise highly disturbing to the commonly received notions of biology. Many of the materialist biological theories that arose in the middle of the eighteenth century were founded upon observations such as these.14

Réaumur also made a significant contribution to physiology in his brilliantly conceived experimental investigation of the process of digestion in birds. He demonstrated the enormous power of the gizzard by forcing several grain-eating birds to swallow tubes of glass and tin. When the animals were opened after two days, the glass tubes were found shattered, the pieces of glass smoothed and polished by the action of the gizzard; the tin tubes were crushed and flattened. In carnivorous birds he showed that digestion was more chemical than mechanical. He enclosed pieces of meat in a tube, the ends of which were closed with fine gratings, and forced a kite to swallow it. When the bird later regurgitated the tube, Réaumur found that the meat had been partially digested. There was no sign of putrefaction. Vegetable matter introduced into the bird’s stomach in the same manner underwent little change.

Academic Activities and Death of Réaumur . Réaumur was perhaps the most prestigious member of the Academy of Sciences during the first half of the eighteenth century. Through his incessant labors and voluminous publications, through his extensive correspondents with scientists both in France and abroad, and through the reflected brilliance of his students, he acquired enormous authority and renown in the European scientific community. Many of the important discoveries of the day were announced by him—for instance, the discoveries of the parthenogenesis of a phids and of the regenerative powers of the hydra. It was also he who announced Musschenbroeck’s discovery of the Leyden jar in 1746.

Réaumur rose quickly in the ranks of the Academy. He was elected pemionnaire mecanicien in May 1711; he was also made director of the Academy twelve times and subdirectory nine times. He was elected to the Royal Society of London, to the Academies of Science of Prussia, Russia, and Sweden, and to the Institute of Bologna.

Réaumur never married, but devoted all his time to his scientific and academic career. From a needy relative he bought the title of commander and intendant of the Royal Military Order of Saint Louis, an honorific office possessing the dignity of a count. Two years before his death he inherited the castle and lordship of La Bermondiere in Maine. There in October 1757 he suffered a fall from his horse while returning from Mass and died. He was buried in the parish church of the nearby village, St.-JuIien-du-Terroux. An inscription dedicated to his memory was placed in the church at the time of its restoration in 1879.

NOTES

1. A président is a chief justice. Hénault was president of the most prestigious court in France, the Parlement of Paris.

2. No éloge was ever published for Guisnée; thus neither his first names nor the date and place of his birth are known.

3. For a discussion of the French Academy of Science’s role in the bureaucracy of the ancien régime, see Roger Hahn, The Anatomy of a Scientific Institution; The Paris Academy of Sciences, 1666–1803 (Berkeley, Calif., 1971).

4. They were collected and published under the title L’Art de convertir le fer forgé en acier, el l’art dadoucir le fer fondue ou de faire des outrages de fer fondu aussi finis que de fer forgé (Paris, 1722).

5. “From the time of Aristotle to the present day I know of but one man who has shown himself Mr. Darwin’s equal in one field of research—and that is Réaumur.” Quoted in Leonard Huxley, Life and Letters of Thomas Henry Huxley, I (New York, 1901), 515.

6.The Natural History of Ants William Morton Wheeler, trans, and ed. (New York, 1926), French text included; histoire des fourmis, Charles Perez, ed., with intro. by E.L. Bouvier; Encyclopédie entomologique, ser. A, XI (Paris, 1928); Histoire des scarabés, P. Lesne and F. Picard, eds., XXXII (Paris, 1955); Les papiers laissés par de Réaumur et le tome VII des Mémoires pour servir à l’histoire des insectes … Introduction du tome VII des Mémories pour servir à l’istorie des insectes, Maurice Caullery, ed., Encyclopédic entomologique, ser. A, XXXIla (Paris, 1929).

7. Jean Torlais, “Une rivalité célèbre: Réaumur et Buffon,” in Presse medicate, 65 (11 June 1958), 1057–1058.

8. Quoted by Wheeler in Natural History of Ants, 29.

9. It is difficult to give an exact English equivalent for the word génie in this context. Réaumur seems to have had in mind their character kite skills. The older English word “ingeniosity” would be etymologically nicer.

10. Réaumur, Mémoires pour servir à l’histoire des insects, I, 42.

11.Ibid, 4–5.

12. Réaumur did not know that the wax is made from special secretions and not directly from the pollen collected by the bee.

13. Réaumur, Memoires …, I, 8.

14. See Aram Vartanian, “Trcmbley’s Polyp, La Mettrie, and Eighteenth-Century French Materialism,” in Journal of the History of Ideas, 11 (1950), 259–286.

BIBLIOGRAPHY

I. Original Works. Complete lists of Réaumur’s works are in William Morton Wheeler’s trans, of Réaumur’s The Natural History of Ants (New York, 1926), 263–274; and Jean Torlais, “Chronologie de la vie et des oeuvres de René-Antoine Ferchault de Réaumur,” in Revue histoire des sciences et de tears applications11 (1958), 1–12, with portrait.

Réaumur’s major works are L’art de convertir le fer forgé en acier, et l’art d’adoucir le fer fondu, on de faire des ouvrages de fer fondu aussi finis que de fer forgé (Paris, 1722), English trans. by Annclie Grünhaldt Sisco, with notes and intro. by Cyril Stanley Smith, Réamur’s Memoirs on Steel and Iron (Chicago, 1956); Mémoires pour servir à l’histoire des insects, 6 vols. (Paris, 1734–1742); Art de faire èclorre et d’èlever en toute saison. des oiseaux domestiques de toutes especes, soil par le moyen de la chaleur du fumier, soit par le moyen de cede du feu ordinaire, 2 vols. (Paris, 1749), 2nd ed. entitled Practique de l’art de faire eclore et d’clever en toute saison des oiseaux donwstiques …. (Paris, 1751), also an English trans, of the 1st ed., The Art of Hatching and Bringing up Domestic Fowls … (London, 1750); and 3 vols, in the Paris Academy of Sciences’ series Description des Arts et Metiers: Art de l’epinglier … avec des additions de M. Duhumel du Monceau … (Paris, 1761); Fahrique des ancres … avec des notes et additions de M. Duhamel (Paris, 1761); and Nouvel art d’adoucir le fer fondu aussi finis que de fer forgé …, with intro. by Duhamel du Monceau (Paris, 1762). Also see the works cited in note 6.

In addition sec Abhandlungen über Thermometrie von … Réaumur …, A. J. von Oettingen, trans., in Ostwalds Klassiker der exakten Wissenschaften, 57 (1894); and Correspondance inedite entre Réaumur et Abraham Trembley, Emile Guyenot, ed. (Geneva, 1943).

II. Secondary Literature. For general biographical information see Jean-Paul Grandjean de Fouchy’s eloge in Histoire de l’ Academic royale des sciences … for 1757 (1762), 201–216; Frederic Lusson, Etude stir Réaumur (La Rochelle, 1875); and Jean Torlais, Réaumur et Ch. Bonnet d’apres leur correspondance inedite (Bordeaux, 1932); Réaumur et sa societe (Bordeaux, 1932); and Un esprit encyclopedique en dehors de “l’ Encyclopedie”: Réaumur, d’apres des documents inedits (Paris, 1936; 2nd ed., rev. and enl., 1961).

On Réaumur’s mathematical papers, see René Taton, “Réaumur matthematicien,” in Revue d’ histoire des sciences et de leurs applications, 11 (1958), 130–133. On Réaumur’s work on iron and steel technology, see A. Bircmbaut, “Réaumur et l’elaboration des produits ferreux,” in Revue d’histoire des sciences …, 11 (1958), 138–166; and A. Portevin, “Réaumur, metallurgiste et chimiste,” in Archives Internationales histoire des sciences, 13 (1960), 99–103. On Réaumur’s thermometer, A. Birembaut, “La contribution de Réaumur a la thcrmometrie,” in Revue d’histoire des sciences …, 11 (1958), 302–329.

On Réaumur as a naturalist, see Pierre Grasse, Réaumur et ranalyse des phenomenes instinctives. Conferences du Palais de la Decouverte, ser. D, no. 48 (Paris, 1957); Jean Torlais, “Réaumur et l’histoire des abeilles,” in Revue dlustoire des sciences …, 11 (1958), 51–67; A. Davy de Virville, “Réaumur botaniste,” ibid., 134–137; Jean Rostand, “Réaumur et les premiers essais de lethargic artificielle,” ibid., 15 (1962), 69–71; and “Réaumur et la resistance des insectes á la congélation,” ibid., 71–72; and Jean Théodorides, “Réaumur (1683–1757) et les insectes sociaux,” in Janus, 48 (1959), 62–76.

On Réaumur’s biology and genetics, see Jean Torlais, “Réaumur philosophe,” in Revue dlustoire des sciences …, 11 (1958), 13–33; Jean Rostand, “Réaumur embryologiste et généticien,” ibid., 33–50. For general background on the problem of preformation, see Jacques Roger, Les sciences de la vie dans la pensee francaise du XVIII’ siècle (Paris, 1971), 326–453, and Réaumur and preformation, 380–384. On Réaumur and Polydactyly, see Bentley Glass, “Mauper-luis, Pioneer of Genetics and Evolution,’ in Bentley Glass, ed., Forerunners of Darwin: 1745–1859 (Baltimore, 1959), 63–66.

On Réaumur’s correspondence, see Pierre Speziali, “Réaumur et les savants genevois. Lettres inedites,” in Revue histoire des sciences …, 11 (1958), 68–80 (which contains eight letters to Gabriel Cramer, Theodore Tronchin, and Andre Roger); Jean Chaia, “Sur une correspondance inedite de Réaumur avec Arthur, premier medecin du roy a Cayenne,” in Episteme, 2 (1968), 37–57, (which contains twelve letters); and Peeter Möörsepp, “Rapports entre le célèbre savant français Réaumur et le Tzar Pierre I,” in Actes du XII Congrés internationale d’histoire des sciences, XI (Paris, 1971), 95–101.

On Réaumur’s last years, see A. Davy de Virville, “Réaumur dans la Mayenne,” in Revue d’histoire des sciences …, 11 (1958), 81–82. The articles on Réaumur in Revue d’histoire des sciences et de leurs applications, 11 (1958), have been collected and published as La vie et l’oeuvre de Réaumur (1683–1757) (Paris, 1962).

J. B. Gough