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The flea is another well known little insect, covered all over with black, hard shelly plates, curiously jointed and folded over one another, in such a manner as to comply with all the nimble motions and activity of the animal. The solar microscope shews it four or five feet long. The scales are curiously polished, and beset about the edges with long spikes; it has six legs, four of which are joined on at the breast. When it leaps, it folds these legs short one within another; so that exerting their spring all at the same instant, it is sufficiently elastic

to carry the creature to an incredible distance.

Two things in this creature seem to deserve our consideration: to wit, their surprising agility, and their prodigious strength. It can leap above a hundred times its own length, as has been, and may be easily proved by experiment. What vigorous muscles!. how weak and sluggish in proportion to its bulk is the horse, the camel, or the elephant, if compared with this puny insect!

Cheese mites, although scarcely visible to the naked eye, are magnified apparently as large as rats; moving through lumps of cheese with surprising agility. Their bodies are round and plump, and thinly beset with very long hairs.

In vinegar and sour paste, a number of animalcules may be seen, exactly resembling eels, and exceedingly lively in their motions.

Skin of a Spider's Leg.

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As spiders cast their skins, and leave them in their web, and as there are skins very different in size to be found in cobwebs, it is very probable they cast their skins frequently this enables us to procure the skin of their legs, which, when magnified, will measure on the screen twenty feet in length, considerable thicker than a man's body, and are covered with bristles surprisingly large.

Mr. Baker says, that the contexture of the web, and their manner of weaving it, are the discovery of the microscope; that the spider has five little teats, from whence a gummy liquor proceeds, which hardens in the air, and becomes a string or thread, strong enough to bear five or six times the weight of the spider's body. The threads are finer or coarser, according

to the size of the spider; and what is very singular, they can wind up or take the thread again into their bodies, and raise themselves up when any thing disturbs them in their descent.

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There is a very great variety in the texture, formation, and ornaments on the wings of insects: some are composed of thin films, supported by strong bony ribs, some of which are covered with short feathers, like the tiles of a house, as in moths and butterflies: some are stuck over with short bristles :

others have divided wings, as the gray and white feathered moth. Many are adorned with rows of feathers along their ridges, and borders of feathers round the edge; some have hairs, and others hooks, placed with great regularity and order.

Those conversant in microscopes, need not be informed, that the beautiful colours on the wings of moths and butterflies, are owing to elegant minute feathers, ending in quills, and placed with great exactness in orderly rows, as, when rubbed off, the holes they come from shew.

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