as foon as the caterpillar ceafes to eat, and prepares to change into a chryfalis

PAGE 186, 1. 10.

Mirror points. The butterflies, adorned with these spots, are called in French, peacock-butterflies. M. de Reaumur nan.es their spots, eye-fpots. The Dutch call thefe butterflies, in their language, peacock's eyes, and peacock's tail; because their pots refemble much thofe fpots like eyes, that adorn the tails of thefe birds. In other refpects, the criticifm of Leffer is not very interefting to Naturalifts; it is of little confequence whit names are given to things, provided people are agreed concerning the things defigned by thef: names; and it is even better, to preserve i proper names already received, than to give more fuitable on s, which are new; becaufe, fcience is interested, that each thing have a fingle name, that the memory of those who learn, may not be ufe efsly burdened: which is but too much the cafe already in botany.

PAGE 186, 1. 24.

As if they were the work of a painter. Of all known animals, there are not any, which, for the beauty and agreeable difpofition of their colours, can be compared to butterflies. There are fome, wh ch cannot be feen, without admiration. And, as if it was not enough, that Nature had lavished on them, whatever is moft beautiful and perfect of this kind, there are, befides, fome of them, where gold, filver, and mother of pearl, appear with wonderful fplendor. Altho' Europe produces many butterflies of extraordinary beauty, they are, in general, however, much inferior to those which come to us from the Indies: befides the advantage which thefe laft have, of being, for the moft part, larger than ours, it would feem, that the brilliance of their colours increafes in proportion to the heat of the climate, of which they are natives.

PAGE 187, 1. 3.

Or rather, thofe feathers. It has been faid above, that thy are not feathers, but fcales, or small laminæ.

PAGE 191, 1. 7.

Regaled with the difb. the Magiftrates of Frankfort. Locufts muft formerly have been a food, known in Judea, and

the

the neighbouring countries; fince Mofes permitted the Jews to eat four forts of them, as the author his obferved above, and the Scripture informs us, that John the Baptift lived on locufts and wild honey.

Befides, it is not in the Indies alone, that infects are confidered by the inhabitants, as a delicate food. Every body knows, with what pleasure Europeans eat the fea-eggs, crabs, lobfters, oyfters, mufcles, and other fheil-fifh. Snails that feed on vines, and even fome il gs, are not rejected. I do not mention the thighs of frogs, vipers or turtle, becaufe, for the reafons I have given above, I do not confider them as infects.

PAGE 193, 1. 4.

*The filk-worm draws from its body, threads. Boyle, in his Effay on the Subtility of fluviums, Ch. II. mentions a lady, who, having taken the trouble to undo the coque of a filkworm, found, according to her calculation, that the thread was about 300 English miles in length-The Author.

There has certainly been fome error here. I have often measured the thread which forms the coque of the filk worm, and I have never in general, found it longer than from 700 to 900 feet. Suppofing, with the author of the Spectacle de la Nature, who cites Boyle, that the thread of a coque is 930 feet long, and weighs two grains and a half; I find, that it would require a thread, 3,428,352 feet long, to make a pound of fik, from which it would follow, fuppo fing these feet standard, that a pound of filk would extend to 228 French leagues, fuppofing each league 15,000 feet long, or 3000 geometrical paces.

PAGE 194, 1. 19.

So far as to make a fuit. I do not believe, that M. Bon carried the matter quite fo far: but we are informed, in the Memoirs of the Royal Academy of Sciences, 1710, that he prefented to the Academy, the year before, ftockings and gloves, made of the webs of fpiders.

This led the Affembly, to recommend to M. de Reaumur, and another member, to follow out the difcoveries of M. Bon. Reaumur did fo, and the following is, in general, the refult of his experiments. He found, that the webs of fpiders, were by no means proper for ufe, because the thread of them is too delicate, requiring ninety to make a thread, equal in strength to that fpun by the filk-worm, 3 G 2

and

and about 18,000 of them, to compose a thread fit for fewing, as ftrong as the threads used for that purpofe, made of falk. There remained, therefore, nothing but the coques which they weave round their eggs, from which any utility could be expected: he examined thefe, and found, that none but those of fuch fpiders as weave webs, with rays proceeding from a centre, round which runs a fpiral thread, could be of any ufe, the coques of the other kinds furnishing but little thread, or that thread not poffeffing the neceffary qualities. It was then to be difcovered, if filk could be made from thofe coques, as cheap as common filk; or if dearer, it would aifo be more beautiful. The first queftion' was foon decided. Although M. Reaumur found in earth-worms, and in the foft fubftance of young feathers, à food agreeable to spiders, and eafily procured, and that thus, the difficulty of providing them with a fufficiency of flies was obviated, he met with another, which he could not remove, and that was, the mutual hatred they bear to one another, which precluded every attempt to breed them together. It would therefore have been neceffary to rear them feparately, which could not have been done without infinite trouble, and confequently without great expence. and confidering, that he found the threads of the coques of fpiders to be five times more flender than thofe of the filkworm, and that it required twelve times more fpiders than filk-worms to furnith the fame quantity of filk, infomuch, that to procure a fingle pound of fpider-filk, he needed almoft eight and twenty thousand coques, which could not be had without breeding a much greater number of spiders, as the females only make them, he was convinced, that fpiderfilk would cost infinitely more than common filk. It only remained, then, to know whether it would be more beautiful; and this, M. de Reaumar was perfuaded would not be the cafe; on the contrary, he found that it had less Juftre, and the reafon he gives for this, is, that the threads which compofe the filk of fpiders, are more delicate, and more crifped, than thofe of the filk-worm.

From all this, we learn, that it is not by rearing fpiders, that we can expect to turn this filk to advantage.. The only means, perhaps, by which we might profit by their labours, would be, by obferving the time when they fly in the air, fufpended by their threads, or when they are preparing for fuch expeditions, and then to fend country people into the fields, to collect thofe threads with rakes.

There

There are certainly times, when in a few hours, a large quantity might be gathered. I have often seen the meadows quite covered with it. Perhaps, by carding and spinning this thread in the manner of flax, it might be turned to fome ufe; at any rate, it would coft very little to try the experi

ment.

PAGE 195, 1. 26.

A manufacture eftablished. However induftrious the Dutch may be, in what relates to trade and commerce, they have never yet attempted the breeding of filk-worms in Holland; those who rear them there, doing it only for their own a mufement. There is but a fingle individual in these Provinces, who has carried it to any confiderable degree. It fucceeded fo weil with him, that it is faid, the filk-worm alone has enabled him to build and maintain a very fine country feat, in the neighbourhood of Utrecht. The ma chine he erected there, and which is moved by the fall of á very small rill of water, deserves to be feen. It turns fix thoufand bobbins, and winds as many coques at the fame time.

PAGE 196, 1. 14.

If one should calculate. This calculation, if I am not miftaken, would, in a dozen of years, amount to five hundred and thirty one thousand, four hundred, and forty one hives, fuppofing that no hives had perished during the time, and that each had regularly produced two fwarms a year.

PAGE 196, 1. 25.

The cochineal is a small worm. The cochineal is not a fmall worm, which produces a scarabæus; it is one of thofe animals, which M. de Reaumur calls Pro-Gall-infects, that is to fay, infects which differ from thofe he calls Gall-infects, only in that thefe laft have the body very fmooth, when they are large; while the others preferve thofe wrinkles or articulations, which give them more the appearance of infects, and make them lefs like galls, than what he calls gallinfects.

The gall-infect, in other refpects, and the pro-gall-insects are both animals with fix feet, and there are many fpecies of them. The largest known, hardly attains the fize of a middling pea. While they are very finall, they are active, and run about with great vivacity, but the females, when

they

they become larger, fix themfelves to fome part of a plant or tree, the fubitance of which they fuck; there they afterwards attain a confiderable bulk, and with it, lofe the pow er of changing place, and even all the external figure of an animal, affuming that, nearly of a gall, into which one would think they were metamorphofed. It is in this mo

tionless and immoveable state, that they receive the intercourfe of the male, which is now transformed into a very fmall fly, is an active animal, and is, in no respect, like the females. Thefe, after the embraces of the male, without changing place, lay their eggs in great numbers, which they pafs from the extremity of their abdomen, and lodge under their belly: they now die, and their body, which ftill remains fixed to the fame fpot, ferves as a cover to the eggs, to preserve them from the injuries of the air, till the young ones are hatched, and iffue from this cadaverous protection, to tranfport themfelves elfew here.

PAGE 197, 1. 2.

Suck the fine red fruit. The juice of the fruit of the Cactus opuntia, is, it is true, very red, and is fo indeed, to fuch a degree, that it changes the colour of the urine of perfons who have eaten of it, into a deep red, like blod? but, it is not the fruit which the cochineal fucks; it is the leaves of the plant which are greer, and have no red juice in them. It is probable, that, as the fap of this plant undergoes in the fruit, that alteration which gives it the red colour, it likewife undergoes a fimilar alteration in the body of the cochineal.

M. de Reaumur, in the fecond Memoir of his 4th volume already cited, enters into a very curious difcuffion on the cochineal and the manner of gathering it. What he there fays, deferves the more confideration, that it is founded on authentic documents, judicially proved, and elucidated by his own obfervations. He concludes, by thewing the importance of thefe infects as an article of revenue, and for this purpose, he quotes a Differtation of M. Neufville the Dutch envoy, who proves, that 700,000 pounds weight of fine cochineal, are every year imported into Europe, and at leaft 180,000 pounds weight of an inferior fort. The first fells for ten florins, ten fous; and the other, for thirty Dutch fous a pound, the whole amounting together to 7,410,000 florins, Dutch money, or upwards of L. 650,000 fterling, which is confe

quently