i6o Mayow 



happen that these opposing salts, even after they have 

 acted upon each other, should reside in the said water 

 with their strength almost unimpaired ? For neither 

 is utterly destroyed, but each of the two performs the 

 operations appropriate to its nature, as was shown 

 above ; while yet in other cases when opposite salts 

 are mixed, either both succumb, after a struggle in 

 which each engages with equal strength, or one of 

 them gains the mastery while the other is completely 

 conquered. 



In regard to this, it is probable that although in the 

 lime and in the water in which it is slaked, the acid salt 

 and the fixed salt combined together are changed into 

 some neutral substance, yet the acid salt and the fixed 

 salt are of such a kind as to be by no means fit for 

 mutually subjugating themselves and destroying their 

 powers. But to make this more intelligible, it will be 

 of advantage, I think, to premise some brief observa- 

 tions on the combination of contrary salts with each 

 other and with other substances. 



OF THE COMBINA TION OF CONTRARY SALTS, AND 

 PRE CI PITA TION 



In the first place, then, it is to be noticed that 

 although acid salts and alkalies pass into a neutral 

 substance when they meet, yet they do not, as is 

 generally supposed, entirely destroy each other. For 

 example, when the acid spirit of salt is coagulated with 

 a volatile salt (and the same explanation applies to 

 sal alkali), although the mixed salts seem to be 

 destroyed, yet they may be separated from each 

 other with their forces unimpaired, as takes place 

 when sal armoniac (or any volatile salt combined with 

 an acid spirit) is distilled with salt of tartar. For in 

 this case whatever of acid there is in the sal armoniac 



