Salts. 127 



Miiriat of ammonia, as well as the pure salt 

 of that name, will deflagrate. But it must be 

 remembered that hydrogen, which is a substance 

 highly combustible, is one of the component 

 parts of ammonia. This then is an imperfection 

 in the definition not easy to be surmounted ; but 

 where objects are numerous and diversified, it is 

 difficult to class them. 



It is obvious from what was stated in the first 

 lecture on chemistry, that all salts are compound 

 bodies. The acids all consist of certain bases 

 or radical principles which give the particular 

 character to the salt, and the acidifying prin- 

 ciple, or oxygen. Of the three alkalies the vola- 

 tile or ammonia is a compound of hydrogen 

 and nitrogen ; and soda and potass have been 

 ascertained to be metallic oxides. 



The most simple state of salts is a mass, 

 white, brittle, and in some degree transparent. 

 Salts in certain degrees of heat, are fluid, like 

 oil, and transparent ; when cooled they return to 

 their former state, and are semi-opake. They 

 differ in their degrees of volatility and fusibility : 

 some fly into vapour with the least heat, others 

 in a violent heat remain nearly fixed ; most of 

 them require to be heated red-hot, yet all may 

 be brought into fusion. 



All saline substances dissolve more or less 

 readily in water. The attraction of salts for 

 water is however different in different salts. 



