AND SUtFlIVROUS ACIDS.

37

CAROLINE.

Its aeriform state is, I suppose, owing to thesmaller proportion of oxygen, which renders itlighter than sulphuric acid ?

MRS. B.

Probably; for by adding oxygen to the weakeracid, it may be converted into the stronger kind.But this change of state may also be connected witha change of affinity with regard to caloric.

EMILY.

And may sulphurous acid be obtained from sul-phuric acid by a diminution of oxygen ?

MRS. B.

Yes; it can be done by bringing any combustiblesubstance in contact with the acid. This decom-position is most easily performed by some of themetals ; these absorb a portion of the oxygen fromthe sulphuric acid, wliich is thus converted intothe sulphurous, and flies off in its gaseous form.

CAROLINE.

And cannot the sulphurous acid itself be de-composed and reduced to sulphur ?