MRS. B.
Very far from it; it is only certain substances which will enter into that peculiar kind of union with oxygen that produces acids, and the number of these is proportionally very small; but all burnt bodies may be considered as belonging either to the class of oxyds, or to that of acids. At a future period, we shall enter more at large into this subject. At present, I have but one circumstance further to point out to your observation respecting acids: it is, that most of them are susceptible of two degrees of acidification, according to the different quantities of oxygen with which their basis combines.
EMILY.
And how are these two degrees of acidification distinguished?
MRS. B.
By the peculiar properties which result from them. The acid we have just made is the first or weakest degree of acidification, and is called sulphureous acid; if it were fully saturated with oxygen, it would be called sulphuric acid. You must therefore remember, that in this, as in all acids, the first degree of acidification is expressed by the termination in ous; the stronger, by the termination in ic.
CAROLINE.
And how is the sulphuric acid made?
MRS. B.
By burning sulphur in pure oxygen gas, and thus rendering its combustion much more complete. I have provided some oxygen gas for this purpose; it is in that bottle, but we must first decant the gas into the glass receiver which stands on the shelf in the bath, and is full of water.