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the muscles which move the jaws may frequently be seen working. The blood may also be observed moving in the transparent part contiguous to the dark central part, but no words can sufficiently describe it.

This creature, after it passes the state of an insect, gets wings, and becomes an inhabitant of the air; and what is most amazing, that although a minute ago it was an inhabitant of the water, it would now be drowned if plunged therein.

A remarkable and singular kind of circulation may be seen by those luminous objects called Medusas, or night qualls, which occasion the luminous appearance in sea water when agitated violently. This circulation may be seen by the naked eye; and though it be perfectly transparent, like the white of an egg, it cannot be conveniently observed with the solar microscope. This object is however of such a singular nature, as not ea sily to be described or understood; for although it has this manifest circulation, yet, if

separated or broken, each part continues to exhibit equally as before the powerful circulation; and this it will continue to show when reduced to very small dimensions, yet, a very trifling agitation will separate it into parts so minute, that although inclosed in a transparent glass tube, nothing can be okserved but water like soup suds.

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The crystallization of salts makes an ele gant appearance by the solar microscope. Sal ammoniac seems preferable to any other salt for this exhibition. A solution of sal ammoniac in water is made, and by dipping a stick therein, a very small quantity is spread evenly on a naroow strip of window glass this being expeditiously placed in the microscope, will, in about half a minute, or less time, throw forth such splendid and

beautiful streams and flashes of crystallization, as is beyond the power of the tongue to describe, or the pencil to paint; for, no drawing can exhibit motion.

The effervescence of acids and alkalis will produce a rapid motion and pleasing appearance, which will cease when the mutual attractive and repulsive powers are balanced, and the whole is completely mixed.

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The Louse is an ugly insect well known, which upon the screen of the solar micros cope appears four or five feet long: it is

commonly bred on the head. People gene-rally think that the louse found on the body is different from that got on the head; but the microscope discovers no such difference: and we may be certain, that when people are dirty, and do not shift their linen frequently, the lice, when they get there, will lay their nits and eggs, where they will breed rapidly, because the nourishment they get on the body, they prefer to what they get on the head. Its magnified appearance is five or six feet long; the motion of its limbs, exceedingly rapid and nimble.

Mr. Baker, in his treatise on the microsscope, vol. 2, page 181, says, that in 8 weeks a louse may see 5000 of its descendants. This was experienced by Mr. Lieuwenhoek, who put two females into a black silk stocking which he wore both day and night; by which he discovered the progression of the increase as before mentioned.

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