with a plain ftone; cardinal Cynthio, whom he made his heir, always profeffing an intention of erecting a monument to his memory, but though he furvived many years, yet he died without putting it into execution. Manfo, to whom he left nothing but his picture, when he came, ten years after his death, and found not fo much as his name infcribed upon the ftone that lay over him, would have taken upon himself the care of erecting a monument, but he was not permitted; however, he procured the words, Hic jacet Torquatus Taffus to be engraven on the ftone that covered his grave. A ftately monument was at last erected to his memory in the church where he was buried, by cardinal Bonifacio Bevilacqua, of an illuftrious family of Ferrara.

He was tall and well shaped, his complexion fair but pale; the hair of his head was of a chefnut colour, that of his beard fomewhat lighter, thick, and bufhy; his forehead was fquare and high, his head large, and the fore-part of it in the latter part of his life, bald; his eye-brows were dark, his eyes full, piercing, and of a clear blue; his nofe large, his lips thin, his teeth well fet and white, his neck well proportioned, his breaft full, his fhoulders broad, and all his limbs were more finewy than fleshy. His voice was ftrong, clear, and folemn; he spoke with deliberation, and generally reiterated his lait words: he feldom laughed, and never to excefs; he was very expert in the exercifes of the body. In his oratory he used little action, and pleafed rather by the beauty and force of his language, than by the graces of gefture and utter

ance. His writings make it unneceffary to mention the natural endowments of his mind, but it is faid of him, that there never was a scholar more humble, a wit more devout, or a man more amiable.

Some account of the life of the celebrated French academift Monfieur DE REAUMUR.

Ene-Anthony Ferchault, lord

of Reaumur, was born at Rochelle in the year 1683: he learned grammar at the place of his birth, and ftudied philofophy at the Jefuits college at Poitieres: in 1699 he went from thence to Bourges, at the invitation of an uncle, where he ftudied the civil law: in 1703 he went to Paris, and applied himfelf wholly to the mathematics and natural philofophy; and in 1708, being then only four-and-twenty years old, he was chofen a member of the royal academy of fciences of that city, and during that and the following year, he described a general method of finding and afcertaining all curves defcribed by the extremity of a right line, the other end of which is moved round a given curve, and by lines which fall upon a given curve under a certain angle greater or less than a right angle.

Thefe are the only geometrical performances that he produced; in the year 1710, he read his obfervations upon the formation of fhells, in which he proved that they grow not like the other parts of the animal body by expanfion, but by the external addition of new parts? He alfo affigned the caufe of the variety, in point of colour, figure, and magnitude which diftinguishes one

fhell

fhell from another. During the experiments which this enquiry led him to make upon fnails, he difcovered a very fingular infect which lives not only upon these animals, but burrows in their bodies, a fituation which he never leaves unless he is forced out of it by the fnail. This enquiry alfo gave occafion to M. Reaumur to account for the progreffive motion of teftaceous animals of different kinds, and to describe and explain an almoft endless variety of organs which the author of nature has adapted to that purpofe, He produced alfo the fame year the natural hiftory of cob-webs. M. Bon, the firft prefident of the chamber of accounts at Monpellier, had fhewn that the webs made by fpiders to depofit their eggs in might be spun into a kind of filk, applicable to useful purposes, but it was ftill neceffary to determine whether spiders could be bred in fufficient numbers, without an expence too great for the undertaking to bear, and M. Reaumur foon found that M. Bon's discovery was a mere matter of curiofity, and that the commercial world could derive no advantage from these webs.

It has been long known, that many marine animals adhere to folid bodies of various kinds, either by an attachment which continues during their existence, or which they can determine at pleasure; but how this attachment was formed, remained a fecret, till it was discovered by M. Reaumur, to whofe enquiries we are indebted

for our knowledge of many organs and materials adapted to that purpofe, of which we had no conception before. In the courfe of this enquiry, M. Reaumur discovered a fifh different from that which furnished the ancients with their Tyrian dye, but which has the fame property in a yet greater degree; upon the fides of this fish there are fmall grains, like thofe of a hard roe, which being broken, yield firft a fine full yellow colour, that upon being exposed for a few minutes to the air becomes a beautiful purple.

About the fame time M. Reaumur made a great variety of experiments, to discover whether the strength of a cord was greater or lefs than the fum of the strength of the threads of which it confifts. It was generally believed that the ftrength of the cord was greater, bnt M. Reaumur's experiments proved it to be lefs, whence it neceffarily follows, that the less a cord differs from an affemblage of parallel threads, i. e. the lefs it is twisted, the ftronger it is *.

It had been long afferted by those who lived on the fea coaft, or the banks of great rivers, that when craw-fifh, crabs, and lobfters, happen to lose a claw, nature produces another in its ftead. This, however, was disbelieved by all but the vulgar, till M. Reaumur put the matter out of difpute, and traced the re-production through all its circumftances, which are even more fingular than the thing itself.

M.

M. Reaumur, after many experiments made with the torpedo, or numb-fifh, discovered that its effect was not produced by an emiffion of torporific particles, as fome have fuppofed, but by the great quicknefs of a ftroke given by this fish to the limb that touches it, by mufcles of a moft admirable ftructure, which are adapted to that purpose.

Thefe difcoveries, however, are chiefly matters of curiofity, thofe which follow are of use.

It had long been a received opinion, that turquoise ftones were found only in Perfia; but M. de Reaumur discovered mines of them in Languedoc; he ascertained the degree of heat neceffary to give them their colour, and the proper form and dimenfions of the furnace; he proved alfo that the turquoife is no more than a foffil bone petrified, coloured by a metallic folution which fire caufes to fpread; and that the turquoifes of France are at least equal in beauty and fize to thofe of the east.

M. de Reaumur alfo difcovered the fecret of making artificial pearls, and the fubftance neceffary to give them their colour, which is caken from a little fifh called able, or ablette. He drew up, at the fame time, a differtation upon the true pearl, which he fuppofed to be a morbid concretion in the body of the animal.

M. de Reaumur foon after pubished the hiftory of the auriferous rivers of France, in which he has given a very particular account of the manner of feparating the grains of gold from the fand with which it is mixed.

Among other memoirs he drew up the following: 1ft, Concern

ing the vaft bank of fofil fhells, which, in Touraine, is dug for manure, called falun: 2d, Upon flints, proving that they are only more penetrated by a ftony juice, or, if the expreffion may be allowed, more fonified than other ftones, though lefs than rock crystal: 3d, Upon the noflock, a fingular plant, which appears only after hard rains in the fummer, under a gelataneous form, and foon after disappears: 4th, Upon the light of dails, a kind of fhell fifh, which fhines in the dark, but lofes its luftre as it grows ftale: 5th, Upon the faci lity with which iron and steel bebecome magnetic by percuffion.

In 1722, he published a work under the title of The art of converting iron into fteel, and of rendering caft iron ductile.

The ufe of iron is well known under the three forms of caft iron, forged or bar-iron, and steel: iron in the firft ftate is fufceptible of fufion, but it is brittle and hard, and can neither be forged by the hammer, nor cut by the chiffel: in the second state it is malleable, and may be both filed and cut, but it is no longer fufible without the addition of a foreign substance: in the third it acquires a very fingular property of becoming hard and brittle, if after it has been made red hot it is dipped into cold water: the extreme brittleness of cast iron makes it unfit for the construction of any thing that is required to be fupple, and still more for any thing upon which it will be neceffary to employ a tool of any kind after it comes out of the font, for no tool can touch it. On the other hand, the manner of converting forged or bar-iron into ftecl, was then wholly unknown in France.

But

Bat M. Reaumur having, in the courfe of other enquiries, found that steel differed from iron only in having more fulphur and more falt in its compofition, undertook to discover the method of giving to iron what was wanting to make it fteel, and at length perfectly fucceeded, fo as to make fteel of what quality he pleased.

The fame experiments, which convinced M. de Reaumur that fteel differed from iron only in having more fulphur and falt, convinced him also that caft iron differed from forged iron, only by having ftill more fulphur and falt than fteel; it was fteel with an excefs of its fpecific difference from forged iron: he therefore fet himself about taking away this excefs, and he fucceeded fo well, as to produce a great variety of utenfils in caft iron, which were as easily wrought as forged iron, and did not cost half the money. However, a manufactory set on foot in France for rendering caft iron fufficiently ductile to be forged and wrought, was, after fome time, difcontinued, and has never been revived fince, though for what reafon does not appear.

For difcovering the fecret of converting iron into fteel, the duke of Orleans being then regent, fcttled a penfion upon M. de Reaumur of 12,000 livres a year, and, at his request, it was fettled upon the academy after his death, to be applied for defraying the expences of future attempts to improve the

arts.

M. de Reaumur alfo difcovered the fecret of making tin, as it was practifed in Germany; and his countrymen, inftructed in that ufeful manufacture, no longer imported tin from abroad.

He invented the art of making porcelain. A few fimple obfervations upon fragments of glass, porcelain, and pottery, convinced him that china was nothing more than a demi-vitrification; now a demi-vitrification may be obtained either by expofing a vitrifiable matter to the action of fire, and withdrawing it before it is perfectly vitrified, or by making a pale of two fubftances, one of which is vitrifiable, and the other not: it was therefore very eafy to difcover by which of thefe methods the porcelain of China was made; nothing more was neceffary than to urge it with a ftrong fire; if it confifted wholly of a vitrifiable matter half vitrified, it would be converted into glafs; if of two fubftances, one of which was not vitrifiable, it would come out of the furnace the fame as it went in this experiment being made, the China porcelain fuffered no alteration, but all the European porcelain was changed into glafs.

But when the China porcelain was thus difcovered to confift of two diftinct fubftances, it was farther neceffary to difcover what they were, and whether France produced them. M. Reaumur accomplished thefe defiderata, and had the fatisfaction to find that the materials for making China porcelain were to be had in France in the fame abundance, and in greater perfection than in India. M. Reaumur alfo contrived a new fpecies of porcelain, confifting only of glafs, annealed a fecond time, with certain eafy precautions, which, though lefs beautiful than other porcelain, is yet a useful dif covery, confidering the great facility and cheapnefs with which it

is made.

M.

M. Reaumur was the first that reduced thermometers to a common ftandard, fo as that the cold indicated by a thermometer in one place, might be compared with the cold indicated by a thermometer in another; in other words, he prescribed rules by which two thermometers might be conftructed, that would exactly coincide with each other through all the changes of heat and cold: he fixed the middle term, or zero, of his divifion of the tube, at the point to which the liquor rifes when the bulb is plunged in water that is beginning to freeze, he prefcribed a method of regulating the divifions in proportion to the quantity of liquor, and not by the aliquot parts of the length of the tube, and he directed how fpirits of wine might be reduced to one certain degree of dilatability. Thermometers conftructed upon thefe principles were called Reaumur's thermometers, and foon took place of all others.

M. de Reaumur invented the art of preferving eggs, and of hatching them; this art had been long known and practifed in Egypt, but to the reft of the world was an impenetrable fecret: M. de Reaumur found out and defcribed many ways of producing an artificial warmth in which chickens might be hatched, and fome by the application of fires used for other purposes; he fhewed how chickens might be hatched in a dunghill; he invented long cages in which the callow brood were preferved in their firft ftate, with fur cafes to them to creep under instead of the hen's bofom, and he prefcribed proper food for them of fuch things as are every where to be procured in great plenty.

He found alfo that eggs might be kept fresh, and fit for incubation, many years, by washing them with a varnish of oil, greafe, or any other fubftance, that would effectually stop the pores of the shell, and prevent the contents from evaporating; by this contrivance eggs may not only be preferved for eating or hatching in the hotteft climates, but the eggs of birds of every kind may be tranfported from one climate to another, and the breed of thofe that could not furvive a long voyage, propagated in the moft diftant part of the world.

While he was employed in thefe difcoveries, he was gradually proceeding in another work, The hiftory of infects, the first volume of which he published in 1734.

This volume contains the hiftory of caterpillars, which he divides into feven claffes, each of a distinct kind and character: He defcribes the manner in which they fubfift, as well under the form of caterpillars as in the chryfalis ftate; the fe veral changes which they undergo; their manner of taking food, and of fpinning their webs.

The fecond volume, which was published in 1736, is a continua tion of the fame fubject, and defcribes caterpillars in their third ftate, that of butterflies, with all the curious particulars relating to their figure and colour, the beautiful duft with which they are pow dered, their coupling and laying their eggs, which the wisdom of Providence has, by an invariable inftinet, directed them to do, where their young may moft conveniently find shelter and food.

The third volume contains the hiftory of moths, not only of thofe which are so pernicious to cloaths and