Where it would be profitable to use it in preference to sulphuric acid, or peculiar circumstances command its use, the utmost care must be taken in generating the gas and carefully purifying it. (See Purification of Carbonic Acid Gas in this Part.) In a distant country, where there was no dependence on regular shipments, the author used muriatic acid, which was at hand, the stock of sulphuric being exhausted, and such or other similar cases may-occur.

Muriatic acid forms in seltzer water and other natural or artificial mineral water an important ingredient; the manufacturer therefore ought to get acquainted with this chemical product.