proceedings of tde rolytechnic association. 443 

 Phosphorus. 



Phosphorus was discovered by Brande in 1669. It is never met in nature 

 in an unconibined state, but occurs in small propoi'tion in phosphate of lime. 



The portion of phosphate of lime in oones varies with the source from 

 which they are obtained. The solidity and fineness of the bones of man- and 

 quadrupeds is owing to a considerable portion of phosphate of lime which 

 they contain. 



One hundred parts of ox bones contain 51 solid gelatin, 37.7 phosphate of 

 lime, 10 carbonate of lime, and one-third of pho.sphate of magnesia. 



In one hundred parts of man's bones there are 81.9 of phosphate of lime. 



Phosphate of lime occurs in small proportion in or is a constituent of the 

 primitive and volcanic rocks, by the gradual decay of which it passes into the 

 soil; from this it is extracted by plants, which accumulate it, particularly in 

 (heir seeds. Phosphorus is a never-failing ingredient, in the substances of 

 which the brain and nei-ves are composed. It is likewise contained in albumen 

 and in filrin, and is present in the form of phosphates of the earths and of 

 the alkalies in the urine and solid excrements uf animals. 



Phosphorus was originally attained from the salts contained in urine, but is 

 now obtained almost exclusively from bones. 



The symbol of phosphorus is P., its eq. 32 ; density «f vapor 4327. (The 

 density of carbonic acid is 1529, not quite one-half of that of vapor of P.) 



Preparation. 



The earth of bones is decomposed by two-thirds its weight of sulj^huric 

 acid, and the insoluble sulphate of lime separated by filtration from the solu- 

 ble phosphoric acid, which passes- through with a quantity of phosphate of 

 lime in solution. The acid liquor is then evaporated to the consistence of a 

 syrup, and mixed with charcoal to form a soft paste, which is rubbed well in a 

 morter and then dried in an iron pot, with constant stirring, till the mass 

 begins to be red hot. It is allowed to cool, and introduced as rapidly as pos- 

 sible into a stoneware retort, previously covered with a coating of fire-clay. 

 The beak of the retort is inserted into a wide copper tube of a few feet in 

 length, the free end of which is bent downward a few inches from its extrem- 

 ity, and the descending portion introduced into a wide mouthed bottle con- 

 taining water enough to just cover the extremity of the tube. 



The heat of the furnace in which the retort is placed is slowly raised for 

 three or four hours, and then urged vigorously till the phosphorus has passed 

 over. The presence of certain gaseous substances, even in minute quantity, . 

 has a remarkable effect in preventing the slow combustion of sulphur ; thus 

 at 66 degrees it is entirely prevented by the presence o 



1 vol. olefiant gas in 450 vols, air, 



1 vol. vapor of sulphuric ether in 150 vols. air. 



1 vol. vapor of naphtha in 1820 vols. air. 



1 vol. vajjor oil of turpentine in 4444 vols. air. 

 And the influence of these gases is not confined to low temperatures, a certain 

 mixture of all of them defending phosphorus from oxidation even at two hun- 

 dred de;irccs. 



