Pulverize 1 ounce of citric acid, and divide it into 24 parts; that
is, 24 scruples, which are to be put into separate small _blue_
papers. Pulverize, also, 1 ounce of the sub-carbonate of soda, and
divide it into 24 like packages, in _white_ paper. When the draught
is to be prepared, put the carbonate into a tumbler, half filled with
water: in another, dissolve the acid in an equal quantity; throw one
into the other, and drink it while effervescing.
A similar preparation may be made by using tartaric acid instead of
the citric.