CHAP. XIV. 



OF THE ATOMIC WEIGHTS OF THE 

 COMBUSTIBLE ACIDS. 



THE acids formed in organized vegetable bodies, 

 or by the action of nitric acid on organized bodies, 

 contain (with a very few exceptions) both car- 

 bon and hydrogen, united to oxygen in various 

 proportions. When these acids are combined 

 with a base, and distilled in a retort, they all 

 give out combustible gases ; most of them form 

 oils, and several of them leave behind them a 

 quantity of charcoal. All of them, therefore, 

 when decomposed by heat, resolve themselves 

 partly into combustible products, while this is 

 not the case with any of the acids composed of 

 a single base united to oxygen, or chlorine, 

 or iodine. This difference has induced me to 

 distinguish the acids with compound bases by 

 the name of combustible acids. 



About thirty combustible acids have been de- 

 scribed by chemists, and distinguished by parti- 

 cular names ; but by far the greater number of 

 these bodies are of rare occurrence, and conse- 

 quently, in a theoretical point of view, of very 

 inferior importance. There are six of them 



G2, 



