outh. 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 Experiments with a Viper._

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

He took a newly-caught viper, and, shutting it up in a small receiver,
extracted the air. At first, upon the air being drawn away, the viper
began to swell; a short time after it gasped and opened its jaws; it
then resumed its former lankness, and began to move up and down within
the receiver, as if to seek for air. After a while, it foamed a
little, leaving the foam sticking to the inside of the glass; soon
after, the body and neck became prodigiously swelled, and a blister
appeared on its back. Within an hour and a half from the time the
receiver was exhausted, the distended viper moved, being yet alive,
though its jaws remained quite stretched; its black tongue reached
beyond the mouth, which had also become black in the inside: in this
situation it continued for three hours; but on the air being
re-admitted, the viper's mouth was presently closed, and soon after
opened again; and these motions continued some time, as if there were
still some remains of life.

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,

First.--That in _atmospheric_ air, HOURS MIN.
The first sparrow lived 3 0
The second sparr