General Principles. 61 



which are chiefly composed of phosphat of lime, it 

 is easily driven off from burnt bones by a stronger 

 acid. But the mode of obtaining it, and its most 

 conspicuous properties, will be detailed more at 

 large when we treat of combustible bodies. It is 

 only necessary at present to mention it as a sim- 

 ple substance, and to notice its combinations. 



Phosphorus, when pure in colour and sub- 

 stance, resembles bees-wax. Its most remark- 

 able property is its very strong attraction for 

 oxygen, from which circumstance it burns spon- 

 taneously in the open air at the temperature 

 of 4-3. That is, in philosophical language, it 

 attracts the oxygen gas from the atmosphere, 

 which becoming condensed, heat and flame are 

 produced. The consequence is, that the phos- 

 phorus becomes oxidized or converted into an 

 acid. Phosphoric acid is heavier than the phos- 

 phorus which produced it in proportion to the 

 quantity of oxygen which is combined with it. 



Phosphorus combines with the other simple 

 combustibles, as well as with many other bodies 

 forming phosphurets. 



VI. SULPHUR is also one of those simple sub- 

 stances which is known to exist pure in a solid 

 state. It is familiar to us under the old homely 

 name of brimstone, and therefore requires no de- 

 scription. It is found combined with many 

 mineral substances, as arsenic, antimony, cop- 

 per, and most of the metallic ores, from which 

 (being very volatile) it is easily driven off by 



D 2 



