XVI 

 KARL WILHELM SCHEELE 



I 742-1 786 



Karl Wilhelm Scheele, who discovered independently of the Eng- 

 lish chemists the double constitution of air, was born in Stralsund, 

 Pomerania, December ip, 1742. At an early age he manifested in- 

 terest in pharmacy, and during his career as an apothecary engaged 

 in various experiments in chemistry. He published his ''Treatise on 

 Air and Fire" in 1777 > He died at Koping, May 21, 1786. 



THE CONSTITUENTS OF AIR* 



1. It is the object and chief business of chemistry to separate 

 skilfully substances into their constituents, to discover their prop- 

 erties, and to compound them in different ways. How difficult it is, 

 however, to carry out such operations with the greatest accuracy, can 

 only be unknown to one who either has never undertaken this oc- 

 cupation, or at least has not done so with sufficient attention. 



2. Hitherto chemical investigators are not agreed as to how many 

 elements or fundamental materials compose all substances. In fact 

 this is one of the most difficult problems ; some indeed hold that there 

 remains no further hope of searching out the elements of substances. 

 Poor comfort for those who feel their greatest pleasure in the in- 

 vestigation of natural things! Far is he mistaken, who endeavours 

 to confine chemistry, this noble science, within such narrow bounds ! 

 Others believe that earth and phlogiston are the things from which 

 all material nature has derived its origin. The majority seem com- 

 pletely attached to the peripatetic elements. 



3. I must admit that I have bestowed no little trouble upon this 



* Translated from Treatise on Air and Fire (i777). 



122 



