But now that the process of forming acids by the combustion of their radicals is known, why should not this method be used for making sulphuric acid?
MRS. B.
This is actually done in most manufactures; but the usual method of preparing sulphuric acid does not consist in burning the sulphur in oxygen gas (as we formerly did by the way of experiment), but in heating it together with another substance, nitre, which yields oxygen in sufficient abundance to render the combustion in common air rapid and complete.
CAROLINE.
This substance, then, answers the same purpose as oxygen gas?
MRS. B.
Exactly. In manufactures the combustion is performed in a leaden chamber, with water at the bottom, to receive the vapour and assist its condensation. The combustion is, however, never so perfect but that a quantity of sulphureous acid is formed at the same time; for you recollect that the sulphureous acid, according to the chemical nomenclature, differs from the sulphuric only by containing less oxygen.
From its own powerful properties, and from the various combinations into which it enters, sulphuric acid is of great importance in many of the arts.
It is used also in medicine in a state of great dilution; for were it taken internally, in a concentrated state, it would prove a most dangerous poison.
CAROLINE.