and boiling at 248 deg.. It is a most powerful oxidizing agent,
and is decomposed with more or less rapidity, by almost all the metals,
to which it yields a portion of its oxygen.

The nitric acid of commerce, is generally the article used by
the Daguerreotypist. This usually contains some chlorine and sulphuric acid.
It is obtained by the distillation of saltpetre with sulphuric acid.
It is employed in the Daguerreotype process for dissolving silver,
preparing chloride or oxide, nitrate of silver, [the former used
in galvanizing,] and in combination with muriatic acid for preparing
chloride of gold, used in gilding. It is also used by some for
preparing the plate.

Acidulated Solution.--This solution is used for cleaning
the surface of the Daguerreotype plate. It has the property
of softening the silver, and bringing it to a state in which it
is very susceptible of being either oxidized or iodized,
hence it contributes to increase the sensibility of the plate.
The proportions are to one drop of acid add from 15 to 20
drops of water, or make the solution about like sharp vinegar
to the taste.

Nitro-Muriatic Acid.--Aqua Regia is a compound menstruum invented
by the alchemists for dissolving gold. It is composed of colorless
nitric acid (aqua-fortis) and ordinary muriatic acid; the mixture
is yellow, and acquires the power of dissolving gold and platinum.
These materials are not properly oxidized; it nearly causes their
combination with chlorine, which is in the Muriatic acid.

Hydrochloric Acid (Muriatic Acid).--This acid forms a valuable