THE GREAT LONDON CHEMISTS 53 



oxymuriatic acid is composed of the same substance (free 

 from water), united to oxygen.' His idea then was that 

 ' when bodies are oxidated in muriatic acid gas, it is by a 

 decomposition of the water contained in that substance, 

 and when they are oxidated in oxymuriatic acid, it is by 

 combination with the oxygen in that body.' Davy believed 

 that the chlorides all contained oxygen. 



In a later paper, read in November 1809, he arrived at 

 the true explanation of these facts. It was based on 

 experiments on the ignition of charcoal to whiteness in 

 muriatic and oxymuriatic gases. No action occurred ; 

 and Davy began to doubt whether, as universally sup- 

 posed, these bodies contain any oxygen. He therefore 

 tried whether compounds produced by the action of oxy- 

 muriatic acid on tin, phosphorus, and sulphur would give 

 with ammonia precipitates of the oxides of these elements, 

 or any compounds containing oxygen; and his experi- 

 ments were attended with negative results. He next con- 

 sidered one argument that the so-called ' oxymuriatic acid ' 

 contained oxygen, viz. the fact that on treatment with 

 rnetals, hydrogen is evolved ; and in a further paper, read 

 in November 1810, he proved that on heating barium or 

 strontium in the gas, one volume of oxygen is liberated 

 for every two volumes of oxymuriatic acid absorbed. This 

 is exactly the amount of oxygen contained in the oxide ; 

 and experiments with other oxides of metals resulted in 

 similar liberation of all the oxygen previously combined 

 with the metal. From ttfese facts, Davy concluded that 

 ' to call a body which is not known to contain oxygen, and 

 which cannot contain muriatic acid, oxymuriatic acid, is 

 contrary to the principles of that nomenclature in which 

 it is adopted ' ; and he therefore proposed for the gas the 

 name chlorine. 



Many derivatives of chlorine were made by Davy for 

 the first time ; among them were the oxygen compounds 



