Chemical PliUosopJnj, 95 



retain it in affixed s/ate, and afterwards to part 

 with it, without alteration, was discovered by the 

 experiments of Father Beccaria, Mr. Canton, 

 Mr. Wilson, and M. De Grosser. The affinity 

 between hght '<And heat, and the similarity of their 

 etFects, in certain cases, have been diligently in- 

 vestigated by Dr. Franklin, Mr. AVedgewood, 

 Messrs. Pictet, Cmaptal, and Dorthes, and 

 especially by Count Rumford and Dr. Herscitel. 

 The researches of M. Berthollet and of Dr. 

 B/VNCROFT, in the philosophy of permanent co- 

 lour}^, upon chemical principles, were mentioned 

 in the preceding chapter. The experiments of 

 i)r. Priestley, the Abbe Tessier, Dr. Ingen- 

 Houz, and others, on the effects of hght upon 

 growing vegetables, and the curious inquiries of 

 Herschel, into the different heating poxver of the 

 different prismatic colours, are also worthy of notice 

 in the list of modern discoveries. The importance 

 of these incjuiries, whether considered as insulated 

 facts, or with reference to systematic chemistry, 

 will readily occur to every scientific reader. 



The discovery of oxygenous gas, or vital air, by 

 Priestley and Scheele, was cursorily noticed iir 

 «i former page. Hydrogen, or inflammable air, 

 had been before observed, but its properties were 

 first examined by Mr. Cavendish,^ in 1766, and 

 afterwards more fully investigated by Priestley, 

 Sgheele, Fontana, Ktrwan, De Morveal, 

 Hassenfr atz, and others. The various- combina- 

 tions of this substance, especially w^ith phosphorus 

 and carbon, were first successfully ex-amined by 

 M. Gengembre and Mr. Kir wan, and by the 

 associated Dutch chemists- Bondt, Dieman, Van 

 Troostwyck., and Lauwerenberg. Jzotic air 

 was discovered in 1772, by Dr. Rutherford ^"^ 



iv Philosophical Transactions for 1 7 66. 



a; See hU DUsertation, Dc Atre M*/>hihco, Edin. I77»r 



