So HISTORY of 4he SOCIETK 



namely, Light and Heat. Though, therefore, the weight of the 

 water generated, and of the gafes combined, may be admitted 

 to be equal, yet it mufl be acknowledged, that two fubftances 

 are loft, which the chemifl: cannot confine in his clofeft vefTel, 

 nor weigh in his fineft balance, and it is going much farther than 

 we are authorifed to do, either by experiment or analogy, to 

 conclude that thefe fubftances have had no efFecfl. As heat and 

 light, in Dr Hutton's fyftem, are compofed of that matter 

 which does not gravitate, the exadl coincidence which M. La- 

 voisier obferved between the weight of the water produced and 

 that of the two elaftic fluids, united in the compofition of it, 

 was no argument, in his eyes, agaiuft the efcape of a very efTen- 

 tial part of the ingredients. 



Pursuing the fame reafoning, he fhews how little ground 

 there is to fuppofe that the heat and light evolved in this expe- 

 riment proceed from the vital air ; and he concludes, that the 

 real explanation of the procefs is, that by burning, the matter of 

 light and heat, or the phlogifton of the hydrogenous gas, is 

 fet at liberty, and is thus enabled to unite with the vital air. 



In the fame manner, on examining what relates to the burn- 

 ing of inflammable bodies, he finds the oxygenous gas uneqtial to 

 the effed of furnifhing by its latent heat, or caloric, the whole of 

 the fenfible heat that is produced. He concludes, therefore^ that 

 the hypothefis of the exiftence of phlogifton in thofe bodies that 

 are termed inflammable, is neceflary to account for the pheno- 

 mena of burning ; phenomena, as he juftly remarks, which are 

 among the moft curious and important of any that are exhibited 

 by the material world. On the whole, it cannot be doubted, 

 that great ingenuity and much found argument are difplayed 

 throughout the whole of this diflfertation, and that whatever be 

 ultimately decided with regard to the principle for which the 

 author fo ftrenuoufly contends, he has made it evident, that the 



conclufions 



