cannot raise them half an inch from each other; for ordinary-sized bladder, of six inches across the widest part will have one side pressed upon the other with a fore equal to 396 pounds' weight.

Cork heavier than Lead.

LET a large piece of cork be pendent from one end a balance beam, and a small piece of lead from the other the lead should rather preponderate. If this apparatus placed under a receiver on the pump, you will find that when the air is exhausted, the lead, which seemed the heaviest body, will ascend, and the cork outweigh the lead Restore the air, and the effect will cease. This pheno menon is only on account of the difference of the size in the two objects. The lead, which owes its heaviness to the operation of the air, yields to a lighter because a larger substance when deprived of its assistance.

The animated Bacchus.

CONSTRUCT a figure of Bacchus, seated on a cask; let his belly be formed by a bladder, and let a tube proceed from his mouth to the cask. Fill this tube with coloured water or wine, then place the whole under the receiver. Exhaust the air, and the liquor will be thrown up into his mouth. While he is drinking, his belly will expand.

The artificial Balloon.

TAKE a bladder containing only a small quantity of air and a piece of lead to it, sufficient to sink it, if immersed in water. Put this apparatus into a jar of water, and place the whole under a receiver. Then exhaust the air, and the bladder will expand, become a balloon lighter than the fluid in which it floats, and ascend, carrying the weight

with it.

Curious Experiment with a Viper.

MANY natural philosophers, in their eagerness to display powers of science, have overlooked one of the first ties of life, humanity; and, with this view, have tortured d killed many harmless animals, to exemplify the azing effects of the air-pump. We, however, will not in the pages of this little work by recommending any ch species of cruelty, which in many instances can merely atify curiosity; but as our readers might like to read the fect on animals, we extract from the learned Boyle an count of his experiment with a viper.

He took a newly-caught viper, and, shutting it up in a all receiver, extracted the air. At first, upon the air eing drawn away, the viper began to swell: a short time ter it gasped and opened its jaws; it then resumed its forer lankness, and began to move up and down within the ceiver, as if to seek for air. After a while, it foamed a ttle, leaving the foam sticking to the inside of the glass: oon after, the body and neck became prodigiously swelled, nd a blister appeared on its back. Within an hour

nd a half from the time the receiver was exhausted, he distended viper moved, being yet alive, though its aws remained quite stretched; its black tongue reached eyond the mouth, which had also become black in the nside in this situation it continued for three hours; but on the air being re-admitted, the viper's mouth was presently losed, and soon after opened again; and these motions continued some time, as if there were still some remains of ife.

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It is thus with animals of every kind; even minute microscopical insects cannot live without air.

Experiments with Sparrows.

COUNT MOROzzo placed successively several full-grown sparrows under a glass receiver, inverted over water. It was filled with atmospheric air, and afterwards with vital air. He found,

The water rose in the vessels eight lines during the life

the first; four during the life of the second; and the thir

produced no absorption.

Second.-In vital air or oxygen,

The first sparrow lived

The second.

The third..

The fourth

The fifth

The sixth

The seventh

The eighth

The ninth.

The tenth.

The above experiments elicit the following conclusions -1. That an animal will live longer in vital than i atmospheric air. -2. That one animal can live in ai in which another has died.-3. That, independently of air some respect must be had to the constitution of the animal for the sixth lived 47 minutes, the fifth only thirty. That there is either an absorption of air, or the productio of a new kind of air, which is absorbed by the water it rises.

AMUSING EXPERIMENTS IN ELECTRICITY.

The animated Feather.

ELECTRIFY a smooth glass tube with a rubber, an hold a small feather at a short distance from it. Th feather will instantly fly to the tube, and adhere to it fo a short time; it will then fly off, and the tube can neve be brought close to the feather till it has touched th side of the room, or some other body that communicate

ith the ground. If, therefore, you take care to keep he tube between the feather and the side of the room, ou may drive it round to all parts of the room without uching it; and, what is very remarkable, the same side of he feather will be constantly opposite the tube.

While the feather is flying before the smooth tube, it ill be immediately attracted by an excited rough tube or stick of wax, and fly continually from one tube to the ther, till the electricity of both is discharged.

The Candle lighted by Electricity.

CHARGE a small coated phial, whose knob is bent utwards so as to hang a little over the body of the phial; hen wrap some loose cotton over the extremity of a long rass pin or wire, so as to stick moderately fast to its ubstance. Next roll this extremity of the pin, which is vrapped up in cotton, in some fine powdered resin; then upply the extremity of the pin or wire to the external Coating of the charged phial, and bring, as quickly as possible, the other extremity, that is wrapped round with cotton, to the knob: the powdered resin takes fire, and Communicates its flame to the cotton, and both together burn long enough to light a candle. Dipping the cotton En oil of turpentine will do as well, if you use a larger sized jar.

Candle Bombs.

PROCURE some small glass bubbles, having a neck about an inch long, with very slender bores, by means of which a small quantity of water is to be introduced into them, and the orifice afterwards closed up. This stalk being put through the wick of a burning candle, the flame boils the water into a steam, and the glass is broken with.a loud explosion.

The Artificial Spider.

Cur a piece of burnt cork, about the size of a pea, into the shape of a spider; make its legs of linen thread, and

H

put a grain or two of lead in it to give it more weight. Suspend it by a fine line of silk between an electrified arch and an excited stick of wax; and it will jump continually from one body to the other, moving its legs at the same time, as if animated, to the great surprise of the unconscious spectator.

The Miraculous Portrait.

GET a large print (suppose of the king) with a frame and glass. Cut the print out at about two inches from the frame all round; then with thin paste fix the border that is left on the inside of the glass, pressing it smooth and close; fill up the vacancy, by covering the glass well with leaf-gold or thin tin-foil, so that it may lie close. Cover likewise the inner edge of the bottom part of the back of the frame with the same tin-foil, and make a communi cation between that and the tinfoil in the middle of the glass; then put in the board, and that side is finished. Next turn up the glass, and cover the fore-side with tin-foil, exactly over that on the back part; and when it is dry, paste over it the panel of the print that was cut out, observing to bring the corresponding parts of the border and panel together, so that the picture will appear as at first, only part of it behind the glass, and part before. Lastly, hold the print horizontally by the top, and place a little moveable gilt crown on the king's head.

Now, if the tin-foil on both sides of the glass be moderately electrified, and another person take hold of the bottom of the frame with one hand, so that his fingers touch the tin-foil, and with the other hand attempt to take off the crown, he will receive a very smart blow, and fail in the attempt. The operator, who holds the frame by the upper end, where there is no tin-foil, feels nothing of the shock, and can touch the face of the king without danger, which he pretends is a test of his loyalty.

The Cup of Tantalus.

You place a cup of any sort of metal on a stool of baked wood or a cake of wax. Fill it to the brim with any