Definition of "bicarbonate"

The next question that occurs relates to the composition of this crystallized carbonate of potash, which I am induced to call bi-carbonate of potash, for the purpose of marking more decidedly the distinction between this salt and that which is commonly called a subcarbonate, and in order to refer at once to the double dose of carbonic acid contained in it.

1814, William Hyde Wollaston, “A synoptic scale of chemical equivalents”, in Philosophical Transactions of the Royal Society, volume 104, page 11