This saline principle which is the product of putrefaction, when separated from the other principles of the body which affords it, and collected by itself, appears either in the form of a liquor, or in that of a concrete salt, according to the different methods used to obtain it. In the former state it is called a _Volatile Urinous Spirit_; and in the latter a _Volatile Urinous Salt_. The qualification of urinous is given it, because, as was said, a great deal thereof is generated in putrefied urine, to which it communicates its smell. It goes also by the general name of a _Volatile Alkali_, whether in a concrete or in a liquid form. The enumeration of its properties will shew why it is called an alkali. Volatile Alkalis, from whatever substance obtained, are all alike, and have all the same properties; differing only according to their degrees of purity. The Volatile Alkali, as well as the Fixed, consists of a certain quantity of acid combined with and entangled by a portion of the earth of the mixt body from which it was obtained; and on that account it has many properties like those of a Fixed Alkali. But there is moreover in its composition a considerable quantity of a fat or oily matter, of which there is none in a Fixed Alkali; and on this account again there is a great difference between them. Thus the Volatility of the Alkali produced by putrefaction, which is the principal difference between it and the other kind of Alkali whose nature it is to be Fixed, must be attributed to the portion of oil which it contains: for there is a certain method of volatilizing Fixed Alkalis by means of a fatty substance. Volatile Alkalis have a great affinity with acids, unite therewith rapidly and with ebullition, and form with them neutral salts, which shoot into crystals, but differ from one another according to the kind of acid employed in the combination. The neutral salts which have a Volatile Alkali for their basis are in general called _Ammoniacal Salts_. That whose acid is the acid of sea-salt is called _Sal Ammoniac_. As this was the first known, it gave name to all the rest. Great quantities of this salt are made in Egypt, and thence brought to us. They sublime it from the soot of cow's dung, which is the fuel of that country, and contains sea-salt, together with a Volatile Alkali, or at least the materials proper for forming it; and consequently all the ingredients that enter into the composition of Sal Ammoniac. See the Memoirs of the Academy of Sciences. The neutral salts formed by combining the acids of nitre and of vitriol with a Volatile Alkali are called, after their acids, _Nitrous Sal Ammoniac_, and _Vitriolic Sal Ammoniac_: the latter, from the name of its inventor, is also called Glauber's _Secret Sal Ammoniac_.