nce,
would be in a continual conflagration, until its ashes would be its
only remains: animals would live with hundred-fold intensity, and
terminate their mortal career in a few hours. On the other hand,
were the atmosphere wholly composed of azote, life could never have
existed, whether animal or vegetable, and the objects of the Creator
in forming this world would not be fulfilled. But the atmosphere is a
wholesome mixture of these two formidable elements, each neutralizing
the other's baneful influence. The life of animals quietly runs
through its allotted space; and the current of nature flows within
prescribed limits, manageably and moderately.

_Tartaric Acid._

Every one knows, that when a large quantity of the juice of grapes is
left to spontaneous fermentation, the result is wine. When wine has
been kept some time to depurate in wooden vessels, it deposits, on the
side of the vessel, a hard crust of dark coloured matter, the taste
of which is sour. This matter is impure; but, when purified by various
crystallizations, it becomes perfectly white and crystalline; and
then it is known in commerce by the name of _cream of tartar_. The
etymology of the singular name, tartar, is uncertain: it is derived
from _tartaros_, as some say, because it occasions pains equal to
those endured in the infernal regions; and, as others say, merely
because this substance deposits itself in the inferior parts of the
cask. Tartaric acid may be obtained from cream of tartar by a
process analogous to that given for obtaining citric acid. It has an
exceedingly acid taste: it dissolves readily in water, and is soluble
in alcohol. Its crystals are of a very irregular shape. In 100 parts,
by weight, there are 12 of water; the remaining 88 parts are the pure
anhydrous acid, composed of 32-39 parts of carbon, 52-97 of oxygen,
and 2-64 of hydrogen. This acid exists abundantly in other fruits, but
especially in the tamarind; in the grape it exists along with citric,
malic, and an acid called _vinic_, which resembles tartaric acid
in many respects, but differs from it in others, and concerning the
nature of which almost nothing is known: these four constitute the
agreeable tartness of the juice of that fruit.

_Oxalic Acid_.

The plant called sorrel is valued for its acidulous taste. This
acidity is owing to the presence of a peculiar acid, which may
be separated from the juice, and from the potash with which it is
combined, by a process a