{ 5-1 ) 



dlately to relate what 1 obferved in lavas la 

 fufion, contained in crucibles of the form 

 and fize before defcribed, and tried by the 

 fame experiments which I had made on 

 glafs and metals. 



The firfl: I ufed were of that fpecies 

 which in the furnace become but Uttle po- 

 rous. The water, w^hen poured upon thefe 

 in a ftate of fufion, for feme inftants re- 

 mained motionlefs ; afterwards it began to 

 boil, and the ebullition continued until it 

 was entirely diffipated. I repeated the ex- 

 periment on the fame lavas, after having 

 taken them out of the furnace, and when 

 they had in part loft their glowing red- 

 nefs. The water, on touching them, arofe 

 in noify bubbles, producing a profufion of 

 vapours ; and, as the lavas became cooler, 

 the quantity of vapours became more abun- 

 dant, at leaft to a certain degree of cool- 

 nefs. Thefe lavas, therefore, did not differ 

 from glafs, copper, and iron, with refpe<5l 

 to their caufing no explofion with water. 



B b 2 I next 



