PHOSPHORUS. 75 



the dark at the common temperature of the atmo- 

 sphere. 



To show this property in a striking manner, 

 write with a stick of it upon black or purple paper, 

 or any other smooth surface ; the writing will be 

 luminous as if on fire. The fiery appearance dis- 

 appears and appears again by blowing upon it. It 

 is necessary, in making this experiment, to cut the 

 phosphorus under water, and to put it into a quill, 

 in order to defend the hands, lest it should take 

 fire ; and great care ought to be taken lest any 

 particle should be left under the nails, or in any 

 other place, for if this were afterwards to take fire 

 it might occasion very serious accidents, as a burn 

 by it is extremely severe. 



Very slight friction is sufficient to inflame phos- 

 phorus. Put a grain of it into brown paper and 

 rub it with some hard body, and it will take fire 

 and inflame the paper. It takes fire spontaneously, 

 and burns rapidly in the open air at 122 Fahr., 

 with a brilliant flame. On this account, it is always 

 kept under water ; and it should never be suffered 

 to lie exposed to the air. 



Phosphorus is obtained by decomposing the 

 phosphoric acid by means of charcoal in a retort. 

 The oxygen of the acid unites to the carbon, form- 

 ing carbonic acid \ and the phosphorus distils over 

 into water. The phosphoric acid is obtained by 

 decomposing calcined bones by sulphuric acid. 

 Bones consist chiefly of phosphate of lime ; and 

 in this process the sulphuric acid joins to the lime, 

 leaving the phosphoric acid free. 



Phosphorus is soluble in oil in small quantity, 

 which is thus rendered luminous. Sulphuric and 

 nitric ether, and ardent spirit, dissolve it, though 

 sparingly, in the cold. 



