204 Chemistry. [Lecture SI. 



tracts the phosphorus from calcined bones. The 

 sulphuric acid expels the phosphoric from the 

 powder of the bones, and seizes on the lime. 

 The sulphate of lime is the powder which is 

 thrown away. The phosphoric acid remains 

 behind, and when heated with charcoal in a re- 

 tort, the oxygen comes away with the carbon in 

 the form of carbonic acid gas. The pure phos- 

 phorus, therefore, comes off into the water in 

 the receiver. 



3d. SULPHUR comes properly after phospho- 

 rus, as it equals it in simplicity, and is changed 

 in the same manner. Sulphur or brimstone is, 

 in fact, an elementary substance, which has, like 

 phosphorus, a strong attraction for the oxygen 

 of the air. When inflamed, therefore, the oxy- 

 gen is drawn from the atmosphere, and, uniting 

 with the sulphur, the heat or fire which the air 

 contained is let loose, and the sulphur, by this 

 process (like the phosphorus) is changed. It 

 assumes the acid character, and becomes sul- 

 phuric acid. When the sulphur is imperfectly 

 oxygenated, it is volatile, in the form of sul- 

 phurous gas, or sulphurous acid. Sulphur unites 

 with the fixed alkalies, and forms sulphurets, or 

 livers of sulphur. 



The attraction of sulphur for lime is so weak 

 as to be overcome by the weakest acid. A simi- 

 lar production to the livers of sulphur may be 

 obtained by the volatile alkali, but by a different 

 process. 



