The breeding of filk-worms, with a view to profit in manufactures, was only introduced into France by Henry IV. in the beginning of the 16th century, contrary to the advice and opinion of Sully, who often remonftrated with his clear-fighted mafter against that project, because he deemed it a chimerical undertaking to attempt to rear them in fuch a cold climate as France. Experience has now fufficiently proved, that the enterprising monarch judged more wifely on this fubject than the fage and cautious minifter; as it is well known that France now produces filk in very confiderable quantities. But though France happily fucceeded in this hopeless experiment, as it was judged at the time, fcarcely an idea feems ever to have been seriously entertained by any one, that it was poffible to rear the filk worm with a view to profit in this country, or to eftablish the filk manufacture on the produce of Britain. Yet we think the facts afcertained by the ingenious and fpirited Mifs Rhodes, go far to prove that it is not only poffible to rear filk-worms on the produce of this country with a view to profit, but that it is even highly probable that they may be here reared with equal, if not with greater advantage than in Italy and other warm countries, where only, till very lately, it was believed they ever could be bred. That the Reader may be enabled to judge for himself in regard to this particular, let him be informed, that our fair experimenter difcovered, in the first place, that the eggs may be preferved in a dormant ftate, in this climate, with the greateft eafe as long as you chufe; and that they can be brought to life whenever you incline, during the fummer months, by merely expofing them to the rays of the fun; fo that there is no danger of their coming before the food provided for them has been produced, or of their remaining dormant while it is in perfection. In the fecond place, fhe has alfo found, that in the cool temperature of our fummer air, the cryfalis remains fo long in a dormant ftate, that fufficient time is allowed to wind off the filk without killing it, whereas in warm climates, where their revivification is much quicker, there is a neceffity of killing the cryfalis, by expofing it to the heat of an oven for a certain length of time, before the cones are wound off (boiling water is not sufficient to kill it), to prevent them from eating their way through the cone. The filk, by the heat it is thus made to fuftain, is confiderably damaged, which never needs be done in this country. III. Where it is neceffary to kill the cryfalis in all thofe cones intended for the best filk, it becomes neceffary alfo to felect a fufficient number of the largest and beft cones, that they may be preferved for producing eggs. All these cones, therefore, are deftroyed, and the filk of them in a great measure wafted by the holes that the moth eats through the cones when hatched;" and thus a great wafte is incurred, which with us would be entirely prevented. IV. With a view to lofe as little as poffible in this way, those who rear filk-worms, in warm climates, fuffer no more, moths to be produced than are fufficient to lay the number of eggs that are barely neceffary for keeping up their stock of worms: fo that, if any accident happens either to these eggs, or to the worms after they are hatched, they muft, for that feafon, lofe the whole produce of their filk-worms. But as, in England, the eggs of all the moths, without exception, might be preferved, if neceffary, without any wafte whatever of the filk, it is impoffible that those who may here follow this bufinefs fhould ever be subjected to the inconvenience above mentioned. V. It is found by experience that thunder is extremely prejudicial to the filk-worms; fo that many millions of them may be killed by a thunder ftorm, and with them the filk they ought to have produced is entirely loft. But as thunder is much more frequent, as well as more violent in warm countries than in England, the lofs arifing from accidents of this nature must be there much oftener experienced than bere; fo that our chance of fuccefs must be much greater on this account than theirs. From all these confiderations it would feem, that filk-worms may be reared in Great Britain with equal, if not with greater probability of fuccess, than in those countries where they have been hitherto reared, with a view to profit in manufactures; and this opinion is confirmed by the obfervations that follow: Mifs Rhodes has found that the filk-worm can be fed upon Jettuce, and kept in perfect good health on that food alone, for four out of five weeks that it ufually exifts in the vermicular ftate; fo that it requires only to be fed about one week on mulberry leaves. Now, if it be confidered that mulberry trees can bear the climate of Britain perfectly well, fo as to produce leaves in as great abundance here during the fummer months, as perhaps in any part of the globe, it feems impoffible to deny that raw filk can be produced here, in any quantity that might be judged proper, at as low a price, or poffibly lower, than in those parts of the world from whence we at prefent obtain it, fhould the following fyftem of economy, or fomething like it, be adopted. It was found by experiment, by Mifs R. that ten thousand filk-worms confumed, in a day, about one bufhel of fresh mulberry leaves. Now, let us, for example, fuppofe that a plantation of mulberries was made of fuch an tent, as to yield ten bufhels of leaves a day during four months each year. In this cafe, it would be proper for the owner to hatch about a hundred thousand eggs, four weeks before the mulberry leaves should have attained their full perfection; the worms to be fed during thefe four weeks on lettuce. At the end of a week or ten days, or (for the present say) a fortnight, let another hatching of the fame number be made. Thefe would be ready to take to the mulberry leaves after the former brood had begun to fpin. And if another hatching fucceeded these, and so on through the whole feafon, it is plain, that thus the mulberry plantation (a fufficient fupply of lettuce being always kept up at the fame time) could rear in one season, at leaft eight (it might be fixteen) broods; but we shall call it ten, that is, one million of worms in a season. Whereas, in the way they are at prefent managed in Italy, that plantation could have fubfifted no more than one hundred thoufand; because, in as far as we can learn, the natives of these countries never have been in the practice of trying to preferve the eggs beyond the time the natural heat of the climate produces them; fo that the whole brood comes into life at one time; and that number never can exceed that which their food is capable to fuftain at once, which by the fuppofition was a hundred thoufand. We are now alfo brought to fee of what importance it is to be able to preserve an inexhaustible ftore of eggs, without any expence, because these are always in readiness to be hatched in any quantities that the supply of food may indicate to be neceffary and in cafe of the deftruction of any part of the brood by thunder, or any other accident, that lofs could be fpeedily retrieved, by hatching a new brood to fupply their place. We may also obferve, that confidered as a manufacture, calculated to give employment to women and children, many would be the advantages from rearing them in fucceffive broods, as is here propofed, for Great Britain, in comparison of having the whole at ence, as in other countries. In the first way, conftant employment would be given for the neceffary hands, for many months, without any extraordinary hurry at one time, the feveral broods coming in regular fucceffion; fo that the cones of one brood would juft be finished when another was ready to begin: whereas in the other cafe, all the work comes only at one time, which then occafions a great hurry,-and idleness afterwards mult enfue. We have enlarged a little on this important article, with a view to bring the fubject as generally as poffible under the confideration of the Public, and to induce fome enterprifing individual to make trial of a plantation of mulberries on the plan here develloped. We fhail briefly mention a few other particulars, taken notice of by our amiable conductress in this pleafing excurfion. Mifs R. found by accurate experiment, that a fingle cone of her filk, produced from a worm that had been fed only one week on mulberry leaves, yielded a thread of four hundred and four yards in length, which when dry weighed three grains. But, upon upon an average, the found that it required about three hundred and fixty cones to yield an ounce of filk; independent of the loofe filk round the cones, and other refufe filk, that muft be carded, which is at leaft equal in weight to the pure filk; fo that, in all, 360 cones yield about two ounces of filk, fine and refuse together. Mifs Rhodes takes notice of one peculiarity attending the mulberry leaves, that was new to us. It is, that no animal feems to prey upon that leaf except the filk-worm alone. Nor did fhe find any other vegetable common with us that was wholesome to the filk-worm excepting lettuce only. It is probable, however, fome other plants may be found which will answer the fame purpofes; and it is worth while to continue to try if fuch can be difcovered. She found that neither Elm, Afb, Vine, Hazel, Lime, Currant, Chefnut, Kidney-bean, Strawberry, nor Rafpberry would do, nor common Cabbage. Lettuce is one of the lactefcent femiflofculous plants, and among thefe, trials fhould be made; especially when it is obferved that thefe plants in general, like the mulberry, are very little liable to be eat by any kind of caterpillars. Have Dandelion, Sow-thistle, and others of the fame nature, been tried? Though moft quadrupeds refufe thefe, we have observed that rabbits prefer them to moft kinds of plants. We congratulate Mifs Rhodes on the honour that he has acquired by thefe experiments; and hope the will have the happinefs of feeing many follow her example. MECHANICS. Under this head we find a defcription of a new chime-clock, invented by Mr. Robert Simpfon, of Ship Court, Westminster, on a principle that is fimple, and it appears to be cafily kept in order; but it could not be understood without a drawing. The fame may be faid of a contrivance, by Mr. Bunce, for stopping the wheel crane, by means of a ball-of which no figure is given. Two contrivances also are mentioned for a temporary canvas covering to be thrown over hay-ricks while building; one by the Rev. Mr. Warren of Pomphlet, near Plymouth, and the other by Mr. Ailway; for an account of which we must refer the curious reader to the book itself. Mr. John Adams, teacher of mathematics, at Edmonton, Middlefex, also gives a defcription of an artificial horizon for determining the apparent altitudes of celestial bodies with great exactnefs, of his own invention. The principle of this improvement confifts in adapting a glafs with parallel planes, inftead of a plane concave glass, to a level. As this difcovery was communicated to Mr. Dollond long ago, who has fince made many of them, which are now fold under the name of the Dollondian horizon; and as these are now well known over moft parts of Europe, a more particular description of it is unneceflary. COLONIES COLONIES and TRA de. We are here told that the Mango-tree, and the true Cinnamon, are now flourishing in the Weft-India iflands, having both produced feeds, fo that there is no probability of their ever being loft there; as well as the Nankeen cotton; with which we suppose most of our Readers are in fome measure acquainted. The plants of the Cinnamon-tree, and the Nankeen cotton, were both captured laft war on board a French Eaft Indiaman, by Lord Rodney, and prefented by him to the Governor of Jamaica, where we are told they now thrive abundantly. With regard to the Mango-tree, we meet with two accounts, which differ in some respects fo far, that we are at a loss how to reconcile them. By the firft account we are told, that "Walter Maynard, being a native of the island of Nevis, in the Weft Indies, and failing from Madras, touched at the island of Bourbon, in his way to Europe; and having tafted the Mangos of that ifland, and finding they were a most delicious fruit, was induced to have fome Mango plants put into pots with earth, in order, if poffible, to plant them in the Weft Indies, and was happy enough to meet with a Weft-India packet at sea, which induced him, at that time, to go in her to the Weft Indies, and was fo fortunate as to establish them in the island of St. Vincent; fince which they have fruited, and are now propagated in almost all the Weft-India islands." This happened in the year 1770. The original tree was deftroyed by the hurricane 1780; but we are told," there are now many trees from the feeds of it that will bear this year" (1784). By another account, we are told that the Mango-tree was planted at a place called the Guinea, in Barbadoes, about the year 1742 or 1743, which did not produce any fruit till the year 1760 or 1761, eighteen or nineteen years after it was planted; and that none of the young trees raised from this feed have yet produced fruit: whereas the St. Vincent's tree feems to have produced fruit in five or fix years from the time of its being planted. Are thefe different kinds of Mangos? It does not appear that the natives knew any thing of the Mangos of Barbadoes about the year 1776; though the original tree had then carried fruit at least nine years. The remainder of this volume confifts of lifts of premiums offered-Prefents given to the Society-Members, &c. &c. of which no abridgment can be given. An-n ART. IV. Dr. EDWARDS's Edition of XENOPHON's Memorabilia, concluded. See Review for October, p. 298. SCH CHOLARS only are interefted in the merits of the edition which is now before us; and by fcholars, doubtless, we fhall not be condemned for aiming at that exactness, which tends to |