122 Chemical P kilo s'ophy. [Chap. II. 



power of the different prismatic colours, are alsa 

 ■worthy of notice in the list of modern discoveries*. 

 The importance of these inquiries, whether con si* 

 dered as insulated facts, or with reference to syste- 

 matic chemistry, will readily occur te every scien- 

 tific reader. 



In 1769 Mr. Gahn, of Sweden, discovered that 

 phosphorus was contained in bones ; and his country- 

 man, Scheele, very soon afterwards invented a me- 

 thod of obtaining this substance from them. The 

 pvoperUes of phosphorus have been also more success- 

 fully investigated, during this period, than ever be- 

 fore, by Margraaf, Guyton, Lavoisier, and Pelletier. 

 The properties and combinations oi carbon have been 

 very ably examined, within a iew years past, by 

 many eminent philosophers. The power of this 

 substance, to correct impurities and to remove dis- 

 agreeable odours, has been shown by the experi- 

 ments of Mr. Lowitz, of Petersburg, and several 

 others. The discovery, by Mr. Tennant, that the 

 diamond is pure carbofi in a state of crystalliza- 

 iion'\, is by no means a small or uninteresting 

 step in the progress of chemical science. 



As the diamond is not affected bv a considerable 

 heat, it was for many ages considered as incombus- 

 tible. Sir Isaac Newton, observing that combusti- 

 bles refract light more powerfully than other bodies^ 

 and that the diamond possesses this property in 

 great perfection, suspected it, from that circum- 

 stance, to be capable of combustion. This singular 

 conjecture was verified in 1694, by the Florentine 

 Academicians, in the presence of Cosmo III, grand 



* See Additional Notes — (V). 



■j" Philosophical Trumactionsy 17^7- 



