262 HISTORY OF CHEMISTEY. 



and sulphur, and mercury, these names were given, rather to save tin. 

 hypothesis, than because the substances were really those usually so 

 called : and thus the supposed analyses proved nothing, as Boyle justly 

 urged against them. 1 



The only real advance in chemical theory, therefore, which we can , 

 ascribe to the school of the three principles, as compared with those 

 who held the ancient dogma of the four elements, is, the acknowledg- 

 ment of the changes produced by the chemist's operations, as bein^ 

 changes which were to be accounted for by the union and separation 

 of substantial elements, or, as thej were sometimes called, of hypos ta- 

 tical principles. The workmen of this school acquired, no doubt, a 

 considerable acquaintance with the results of the kinds of processes 

 which they pursued ; they applied their knowledge to the preparation 

 of new medicines ; and some of them, as Paracelsus and Van Helmont, 

 attained, in this way, to great fame and distinction : but their merits, 

 as regards theoretical chemistry, consist only in a truer conception of 

 the problem, and of the mode of attempting its solution, than their 

 predecessors had entertained. 



This step is well marked by a word which, about the time of which 

 we speak, was introduced to denote the chemist's employment. It was 

 called the Spagiric art, (often misspelt Spagyricj) from two Greek 

 words, (tfiraw, dyei'pw,) which mean to separate parts, and to unite 

 them. These two processes, or in more modern language, analysis 

 and synthesis, constitute the whole business of the chemist. We are 

 not making a fanciful arrangement, therefore, when we mark the recog- 

 nition of this object as a step in the progress of chemistry. I now 

 proceed to consider the manner in which the conditions of this analy- 

 sis and synthesis were further developed. 



CHAPTER II. 

 DOCTRINE OF ACID AND ALKALI. SYLVIUS. 



AMONG the results of mixture observed by chemists, were many 

 instances in which two ingredients, each in itself pungent or 

 destructive, being put together, became mild and inoperative ; each 



1 Shaw's Boyle. Skeptical Clnjmi t, pp. 312, 313 tfcc. 



