LEROY C. COOLEY. 33 



the discovery of some products, such as caustic soda, 

 nitric and sulphuric acids, and by the introduction of a 

 few chemical processes, such as distillation and filtra- 

 tion. But we find little definite knowledge of the com- 

 position of these isolated compounds ; little fruitful ap- 

 plication of these processes; no classification, no expla- 

 nation, no generalization, and hence no living science. 

 Alchemy was false, fruitless, dead. 



Now, mark the occurrence of the first sign of vitality. 

 A new doctrine — the theory of the three elements — arose 

 to vanquish the speculation of Aristotle in regard to the 

 composition of matter, which had held possession of 

 men's minds for nineteen hundred years. The father of 

 this new theory was Paracelsus (1493-1541) ; and Para- 

 celsus was the first of the alchemists to break away from 

 the ambition to transmute baser metals into gold. He, 

 great physician as he was, perceived in the materials of 

 alchemy powerful agents to benefit the human race by 

 curing or preventing disease. 



This higher motive turned men's minds into a new 

 channel. A better study of the properties of bodies was 

 begun. Some insight into the composition of com- 

 pounds was acquired. Ideas of the relation of chemical 

 changes to chemical causes took root. And, as Para- 

 celsus was followed at considerable intervals, along the 

 sixteenth century, by Agricola, Sylvius, Boyle, Hooke, 

 Mayow, Becker, and Stall], these new conceptions be- 

 came clearer and broader, until, within less than one 

 hundred years, they had developed into the first con- 

 sistent theory of the composition of bodies and of the 

 chemical changes which they undergo. 



Nor is this all. Reading the history of that century a 

 little more carefully, we discover that long before the 

 end of it chemistry had not only rejected the false and 

 degrading motives of the alchemists, but it had also 

 outgrown the better ambition of Paracelsus. For, just 



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