156 Fossils. 



or saline substances; for a saline sub- 

 stance, in its extended chemical sense, 

 means a substance that has some taste, 

 and is soluble in water. These sub- 

 stances, however, do not strictly and ex- 

 clusively belong to the fossil department, 

 but are obtained also from animal and 

 vegetable substances. They are the most 

 active agents in creation. They give 

 bodies their consistency ; preserve them 

 from corruption, and render them sa- 

 voury. 



Alkalies are distinguishable by their 

 acrid, burning, and urinous taste, their 

 causticity, their singular action on the 

 skin and all animal substances, the quali- 

 ty of changing the blue colour of violets 

 to a green, and even a greenish yellow, 

 and deliquescency. We are acquainted 

 with three species, potash, soda, and 

 ammonia. The first and second have 

 been called fixed alkalies, because they 

 melt and grow red in the fire before 

 they become volatile ; the third has been 

 named volatile alkali, from possessing the 

 opposite property. 



Potash is known by the following char- 

 acters :It is dry, solid, white, and very 



