CH. xvin THE CLASSIFICATION OF THE ELEMENTS 449 



are said to be composed, and into which they are ultimately 

 resolved" (ibid. p. 16). But Boyle insisted that "a man 

 may rationally enough retain some doubts concerning the 

 very number of those material ingredients of mixed bodies, 

 which some would have us call elements and others prin- 

 ciples" (ibid. p. 10), and urged that the problem must be 

 settled rather by experiments than by abstract reasoning. 



Although Boyle was able to combat very effectively the 

 idea that the number of elements was limited to three or 

 four, more than a century elapsed before it was possible to 

 compile a reasonable list of the chemical elements, or to 

 make any serious attempt to classify them. But as soon 

 as the discovery of oxygen had been followed by the proof 

 of the composite character of water, Lavoisier was able to 

 set out, in 1789, a list of some thirty elements, which was 

 increased to fifty in the hands of Berzelius (1819), and now 

 amounts to more than eighty. These elements, with their 

 atomic weights, are set out in Table F, p. 491. 



Lavoisier's classification of the elements (1789), In 

 his Elementary Treatise, Lavoisier classified the elements as 

 follows (Works, I. 135) : 



Simple substances 

 belonging to the 

 three kingdoms, 

 which may be re- 

 garded as the ele- 1 TT 

 ments of bodies. [ H y dr g en 



I Sulphur 

 Phosphorus 

 Carbon 

 Muriatic radical 

 Fluoric radical 3 

 Boric radical 3 

 ( Lime 



' Simple substances, I ^ a | n a esia 



2 Simple sub- 

 stances, 

 metallic, 

 oxidisable, 

 and 

 salifiable. 



1 Silica 



'Antimony 



Silver 



Arsenic 



Bismuth 



Cobalt 



Copper 



Tin 



Iron 



Manganese 



Mercury 



Molybdenum 



Nickel 



Gold 



Platinum 



Lead 



Tungsten 

 \Zinc 



1 Lavoisier considered it as " probable that the four salifiable earths 

 set out above contain oxygen " ( Works, I. 126), but he was not able to 



G G 



