216 MODERN SCIENCE READER 



he recognized that respiration too, was a process of organic 

 combustion. 



Logical and consistent as Lavoisier's method appears to 

 the unprejudiced mind, it failed to appeal to some of the 

 most eminent men of his time. Thoroughly accustomed to 

 the inverted principles of the phlogistic doctrine, those 

 men adhered to them as firmly as fanatics will adhere to 

 an absurd creed, and some of them, including Priestley, 

 himself the discoverer of oxygen, died believers in phlo- 

 giston. Nevertheless, Lavoisier lived to see the light of 

 his system spread over the entire scientific world, and turn 

 chaos into order. He had established a rigid correspond- 

 ence between the law of indestructibility and chemical 

 transformations, and had thus built the first bridge between 

 an abstract principle and the world of chemical phenomena. 

 The concept element was now correctly applied to oxygen, 

 hydrogen, carbon, sulphur, phosphorus and the metals then 

 known in the free state; the concept compound was cor- 

 rectly applied to water and the oxides of the metals. True 

 enough, in his list of elements (1787) Lavoisier included 

 also light and heat and the compounds potash, soda and 

 lime; while, on the other hand, he considered the element 

 chlorine as a compound containing oxygen. But this did 

 not interfere with further progress. The first bridge of 

 chemistry was firmly established, and the lingering errors 

 were rectified (mainly by Sir Humphry Davy) early in 

 the nineteenth century. The development of another cor- 

 respondenceviz : that between the hypothesis of the 

 atomic constitution of matter and the quantitative composi- 

 tion of substances has been already noted in a preceding 

 section of this article. Here it may be observed that the 

 law of multiple proportions was first discovered by Richter 

 (1762-1807), and that Proust (1754-1826) continued Rich- 

 ter 's researches and clearly demonstrated the law in course 

 of a controversy with Berthollet. Dalton (1804) re-dis- 

 covered the law deductively and then proved it experimen- 

 tally ; he was thus the first to establish a rational connection 



