222 CHEMISTRY 



transitional, I might almost say a formative, period of its existence. 

 It was just emerging from the morasses of a philosophy unchecked by 

 experiment, and from the vagaries of the alchemists, and was assum- 

 ing something like its present form. A goodly mass of data had been 

 gathered ; they were partly classified, and the work of interpretation 

 was successfully begun. The analyses of air and water, the discrimin- 

 ation between elements and compounds, and a recognition of the 

 constancy of mass, had laid the foundations of the new science. This 

 word "new" I use advisedly. In its earlier days chemistry was only 

 an empirical art, in which discoveries were made by chance, and 

 remembered because of their utility. Chemical facts were secrets in 

 the hands of artisans, or held by initiated priesthoods; and when 

 they were recorded at all it was only in the form of useful recipes 

 or as medical prescriptions. As a science, as an organized body of 

 knowledge with a philosophy of its own, chemistry hardly existed 

 before the time of Boyle. Alchemy, groping in the darkness, had 

 made useful discoveries; but their successful correlation was an 

 affair of a much later period. To Lavoisier, more than to any other 

 one man, the transformation of chemistry from an art into a science 

 must be ascribed. There were greater discoverers than Lavoisier, 

 perhaps, but he was the organizing spirit, and his proof that matter 

 was indestructible made quantitative chemistry a possibility. With- 

 out such a basis a rational science would be almost inconceivable. 

 It is a necessary complement to the older philosophical maxim that 

 from nothing nothing can be made. Creation and destruction are 

 equally beyond our powers a truism which the ancients may have 

 apprehended, but which before the time of Lavoisier rested on spec- 

 ulation alone. Indeed, the conception was defective until the middle 

 of the nineteenth century, when the doctrine of the conservation of 

 energy raised it to completion. 



Let us now return, to the opening of the century and see how mat- 

 ters stood. The simpler gases, acids, and bases, and the commoner 

 metals were known, and many compounds had been more or less 

 completely examined. Richter and Fischer had shown that reactions 

 took place in proportions which exhibited simple relations to one 

 another; the doctrine of phlogiston had ceased to dominate chemical 

 opinion, and the law of definite proportions, despite the opposition 

 of Berthollet, was generally received. That chemical changes should 

 be governed by fixed quantitative laws was a natural condition to 

 expect, but it needed both proof and explanation. So many reason- 

 able theories had already broken down that a healthy skepticism 

 prevailed, and chemists demanded concrete evidence in favor of 

 every proposition that philosophy might offer for their edification. 

 Rubbish had been cleared away, what structure should rise in its 

 place? An answer to this question was speedily forthcoming. 



