{ 481 ) 



KOTES ON CHAPTER IL 



Stahl. p. 79. 



(jEORGE Ernest Stahl was born in Franconia, in 1660, 

 and died in 1734, in the 75th year of his age. He was un- 

 doubtedly a man of great talents and learning, and the author 

 of many valuable works; the most important of which re- 

 late to his systems of Medicine and of Chemistry. He pub- 

 lished an edition of ih^Phi/sica Subterranea of Becher, after 

 the death of that great Chemist, and adopted the theory which 

 this work displayed; but he simplified and improved it so 

 much, that he made it entirely his own; and accordingly it 

 has been ever since known by the name of the Stalilian 

 theory. 



Latent Heat. p. 8 1 . 



The doctrine of Latent Heat was first taught by Dr. 

 Black, of the University of Edinburgh, in the year 1757. 

 His discovery, and the doctrine which he founded on this dis- 

 covery, may be considered as comprized in the following 

 propositions. Whenever a solid is converted into a Jiiiidf it 

 combines with a certain portion of caloric, without any aug- 

 mentation of its temperature, and it is this portion of caloric 

 which occasions the change. When this fluid is re-converted 

 into a solid, the caloric which produced the fluidity leaves it 

 without any diminution of its temperature; and it is this ab- 

 straction which occasions the change. Thus the combina- 

 tion of a certain portion of caloric with ice causes it to be- 

 come water J and the abstraction of a certain portion of calo- 

 ric from water causes it to become ice. Water, then, is a 

 compound of ice and caloric; and, in general, all fluids are 

 ^■ombinations of the solid to which they may be converted by- 

 cold, and a certain portion of caloric. Tlie same principle, 

 accoiding to diis philosopher, applies to the conversion of 

 liquids into clastic fluids, or the reverse ; this conversion and 

 re-conversion depending on the addition or abstraction of ca- 

 loric. To this caloric Dr. Black gave the name of latent 

 htaf. because its presence is not indicated by the thermometer. 



