INTR OD UCTION. 7 



about finding it out for himself. He knew that 

 Brandt, who died shortly afterwards, had devoted 

 most of his life to experiments on urine, and he 

 felt convinced that phosphorus must have been 

 obtained from that liquid. After many and varied 

 experiments, quite unsuccessful, Kunkel at last 

 obtained (in the year 1674) the substance he sought 

 after so long and so obstinately.* 



In the year 1675, another chemist, Baudoin, 

 prepared a new "phosphorus," or shining sub- 

 stance, by calcining nitrate of lime. Since then, 

 many substances which shine in the dark after ex- 

 posure to the sun, have been discovered. One of 

 the most remarkable, perhaps, is "Canton's Phos- 

 phorus," or sulphuret of calcium, obtained accord- 

 ing to the author just named ' ' by heating a mix- 

 ture of three parts of sifted calcined oyster- shells 

 with one part of sulphur to an intense heat for one 

 hour." It can also be prepared by calcining 

 plaster of Paris with common charcoal. 



The peculiar and sometimes extremely vivid 

 phosphorescence of the sea was known in anti- 

 quity. Pliny speaks of it, and of the phosphores- 

 cence of certain Medusae. But it was not till long 

 afterwards that the cause of this wonderful phe- 



* Some authors state that phosphorus was discovered in Eng- 

 land, about the same time, by Robert Boyle. In 1769, G-ahn, 

 the celebrated Swedish mineralogist, discovered it in bones, and 

 published, with the illustrious Scheele, a new process for extract- 

 ing it, which is similar to the one practised at the present day. 



