Imágenes de páginas

The breeding of silk-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 remonstrated with his clear-sighted master against that project, because he deemed it a chimerical undertaking to attempt to rear them in such a cold climate as France. Experience has now sufficiently proved, that the enterprising monarcb judged more wiseiy on this fubje&t than the faye and cautious minister ; as it is well known that France now produces Gilk in very considerable quantities. But though France happily succeeded in this hopeless experiment, as it was judged at the time, scarcely an idea seems ever to have been seriously entertained by any one, that it was possible to rear the filk.worm with a view to profit in this country, or to establith the filk manufacture on the produce of Britain. Yet we think the fa&s ascertained by the ingenious and spirited Miss Rhodes, go far to prove that it is no! only possible 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 discovered, in the first place, that the eggs may be preserved in a dormant state, in this climate, with the greatest ease as long as you chuse; and that they can be brought to life whenever you incline, during the summer months, by merely expofing them to the rays of the fun; so that there is no danger of their coming before the food provided for them bas been produced, or of their remaining dormant while it is in perfection.

In the second place, she has also found, that in the cool temperature of our summer air, the crysalis remains so long in a dormant state, that sufficient time is allowed to wind off the filk without killing it, whereas in warm climates, where their revi. vification is much quicker, there is a necessity 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 suftain, is considerably damaged, which never needs be done in this country.

III. Where it is necessary to kill the crysalis in all those cones intended for the best filk, it becomes necessary also to select a sufficient number of the largest and beft cones, that they may be preserved for producing eggs. All these cones, therefore, are

destroyed, and the filk of them in a great measure wafted by the · holes that the moth eats through the cones when hatched; and


Ee 4

thus a great waste is incurred, which with us would be entirely prevented.

IV. With a view to lose as little as poffible in this way, those who rear filk-worms, in warm climates, suffer no more moths to be produced than are sufficient to lay the number of eggs that are barely necessary for keeping up their stock of worms: so that, if any accident happens either to these eggs, or to the worms after they are; hatched, they must, for that leason, lose the wbole produce of their filk-worms. But as, in England, the eggs of all the moths, without exception, might be preserved, if neces. sary, without any waste whatever of the filk, it is impossible that those who may here follow this business should ever be subjected to the inconvenience above mentioned.

V. It is found by experience that thunder is extremely prejudicial to the filk-worms ; so that many millions of them may be killed by a thunder storm, 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 Eng. land, the loss arising from accidents of this nature muft be there nuch oftener experienced than bere ; so that our chance of suc. cess muft be much greater on this account than theirs.

From all these considerations it would seem, that Gilk-worms may be reared in Great Britain with equal, if not with greater probability of success, than in those countries where they have been hitherto reared, with a view to profit in manufactures; and this opinion is confirmed by the observations that follow :

Miss Rhodes has found that the filk-worm can be fed upon Jettuce, and kept in perfect good bealth on that food alone, for four out of five weeks that it usually exists in the vermicular state; so that it requires only to be fed about one week on mula berry leaves. Now, if it be considered that mulberry trees can bear the climate of Britain perfe&tly well, so as to produce leaves in as great abundance here during the summer months, as perhaps in any part of the globe, it seems 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 present obtain it, thould the following fyftem of economy, or something like it, be adopted.

It was found by experiment, by Miss R. that ten thousand filk-worms consumed, in a day, about one buthel of fresh mulberry leaves. Now, let us, for example, suppose that a plantation of mulberries was made of such an .tent, as to yield ten bufhels of leaves a day during four months each year. In this case, it would be proper for the owner to hatch about a hundred thousand eggs, four weeks before the mulberry leaves Ihould have attained their full perfection; the worms to be fed during these four weeks on lectuce. At the end of a week or ten days,



[ocr errors]

or (for the present say) a fortnight, let another hatching of the same number be made. These would be ready to take to the mulberry leaves after the former brood had begun to spin. And if another batching succeeded these, and so on through the whole season, it is plain, that thus the mulberry plantation (a sufficient supply of lettuce being always kept up at the same time) could sear in one season, at least 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 present managed in Italy, that plantation could have subsisted no more than one hundred thousand, because, in as far as we can learn, the natives of these countries never have been in the practice of trying to preserve the eggs beyond the time the natural heat of the climate produces them; so that the whole brobd comes into life at one time; and that number never can exceed that which their food is capable to sustain at once, which by the supposition was a hundred thou. sand.

We are now also brought to fee of what importance it is to be able to preserve an inexhaustible store of eggs, without any expence, because these are always in readiness to be batched in any quantities that the supply of food may indicate to be necessary and in case of the destruction of any part of the brood by thunder, or any other accident, that loss could be speedily retrieved, by hatching a new brood to supply their place.

We may also observe, that considered as a manufacture, calculated to give employment to women and children, many would be the advantages from rearing them in fucceffive broods, as is bere proposed, for Great Britain, in comparison of having the whole at ance, as in other countries. In the first way, conftant employment would be given for the necessary hands, for many months, without any extraordinary hurry at one time, the several broods coming in regular succession ; so that the cones of one brood would just be finished when another was ready to begin : whereas in the other case, all the work comes only at one time, which then occasions a great hurry,---and idleness afterwards mult ensue.

We have enlarged a little on this important article, with a view to bring the subject as generally as possible under the confideration of the Public, and to induce fome enterprising india vidual to make trial of a plantation of mulberries on the plan bere develloped. We shall briefly mention a few other particu- . lars, taken notice of by our amiable condu&ress in this pleafing excursion,

Miss R. found by accurate experiment, that a single cone of ber folk, 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 an average, sbe found that it required about three hundred and fixty cones to yield an ounce of silk; independent of the loose silk round the cones, and other refuse filk, that muft be carded, which is at leaft equal in weight to the pure filk; so that, in all, 360 cones yield about two ounces of silk, fine and refuse together.

Miss Rhodes takes notice of one peculiarity attending the mulberry leaves, that was new to us. It is, that no animal seems to prey upon that leaf except the filk-worm alone. Nor did the find

any other vegetable common with us that was wholesome to the folk.worm excepting lettuce only. It is probable, however, some other plants may be found which will answer the fame pure poses; and it is worth while to continue to try if such can be dif. covered. She found that neither Elm, Ah, Vine, Hazel, Lime, Cur. rant, Chefnut, Kidney-bear, Strawberry, nor Raspberry would do, nor common Cabbage. Lettuce is one of the lacteicent semiflosculous plants, and among these, trials should be made ; especially when it is observed that these plants in general, like the mulberry, are very little liable to be ear by any kind of caterpillars. Have Dandelion, Sow-thistle, and others of the same nature, been tried ! Though moft quadrupeds refuse these, we have observed that Tabbits prefer them to moft kinds of plants.

We congratulate Mifs Rhodes on the honour that the has acquired by these experiments; and hope fhe will have the bappi. ness of seeing many follow her example.

MECHANIC Ş. Under this head we find a description of a new chime-clock, invented by Mr. Robert Simpson, of Ship Court, Westminster, on a principle that is fimple, and it appears to be easily kept in order ; but it could not be understood without a.drawing. The fame may be raid of a conuivance, 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 canvass covering to be thrown over hay-ricks while building ; one by the Rev. Mr. Warren of Pompblet, near Plymouth, and the other by Mr. Ailway; for an account of which we muft refer the curious reader to the book itself. Mr. John Adams, teacher of mathematics, at Edmonton, Middlesex, also gives a description of an artificial horizon for determining the apparent altitudes of celestial bodies with great exactness, of his own invention. The principle of this improvement confifts in adapting a glass with parallel planes, inftead of a plane concave glals, to a level. As this discovery was communicated to Mr. Dollond long ago, who has since made many of them, which are now fold under the name of the Dollondian horizon; and as these are now well known over most parts of Europe, a more partie cular description of it is unnecessary.


[ocr errors]

COLONIES and TRADE. We are here told that the Mango-tree, and the true Cinnamon, are now flourishing in the West-India islands, having both produced seeds, so that there is no probability of their ever being lost there; as well as the Nankeen cotton ; with which we fuppose most of our Readers are in some measure acquainted. The plants of the Cinnamon-tree, and the Nankeen cotton, were both captured last war on board a French East Indiaman, by Lord Rodney, and presented by bim to the Governor of Jaa maica, where we are told they now thrive abundantly. With regard to the Mango-tree, we meet with two accounts, which differ in some respects so far, that we are at a loss how to reconcile them. By the first account we are cold, that “ Walter Maynard, being a native of the isand of Nevis, in the West Indies, and failing from Madras, touched at the illand of Bourbon, in his way to Europe ; and having tafted the Mangos that island, and finding they were a most delicious fruit, was induced to have some Mango plants put into pots with earth, in order, if possible, to plant them in the Weft Indies, and was happy enough to meet with a West-India packet at sea, which induced him, at that time, to go in her to the West Indies, and was so 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 isands.". This happened in the year 1770. The original tree was destroyed by the burricane 1780; but we are told," there are now many trees from the seeds 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, wbich 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 seed have

yet produced fruit: whereas the St. Vincent's tree seems to have produced fruit in five or six years from the time of its being planted. Are these 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 consists of lifts of premiums offered - Presents given to the Society-Members, &c. &c. of which no abridgment can be given.

Ann Art. IV. Dr. EDWARDS's Edition of XENOPHON's Memorabilia,

concluded. See Review for October, p. 298. CHOLARS only are interested in the merits of the edition

which is now before us; and by scholars, doubtless, we Mall not be condemned for aiming at that exactness, which tends


[ocr errors]
« AnteriorContinuar »