52 THE ALUMNI JOURNAL 



Scheele thought this gas was a compound and called it Dephlog- 

 isticated Muriatic Acid. Its elementary character was established 

 in 1810 bv Davy. He named it Chlorine on account of its greenish 

 color. 



Nor was this all, for this self-same fertile year saw his discovery 

 of Oxygen — independently of Priestley's revelation — by heating 

 Manganese Dioxide to redness in an iron or clay retort : 



3MnO, = Mn,,p, + O, 



Subsequently Scheele found an improved method of obtaining 

 this gas — by heating Manganese Dioxide with Sulphuric Acid. 

 When Manganese Dioxide is heated alone, 100 grams of it yield 

 8-51 liters of Oxygen, but when treated with Sulphuric Acid, 100 

 grams produce 12.82 liters of Oxygen. The reaction is now familiar 

 to every novice, and medical and pharmaceutical colleges ask it in the 

 early quizzes : 

 . 2MnO, -h 2H,SO, = 2MnSO , + 2H,0 + O, 



He shrewdly speculated as to its function in respiration and the 

 growth of plants, and computed the amount of Oxvgen in the at- 

 mosphere correctly. The term Oxygen (so named by Lavoisier) 

 means "acid producer" and is therefore a misnomer, as all acids do 

 not contain Oxygen. Hydrogen should be called Ox^'gen, because 

 all acids contain Hydrogen. 



Previously to the discovery of Oxygen, Professor Daniel Ruther- 

 ford of the University of Edinburgh, observed that by absorbing 

 the Carbon Dioxide produced bv respiration in an enclosed volume 

 of air, the remaining gas would support neither combustion nor 

 respiration. But it took a long time for scientific news to reach the 

 sequestered (to use Washington Irving's favorite adjective) Swedish 

 town in those days, and just as Scheele had discovered Oxygen 

 independently of Priestley, he also discovered Nitrogen without 

 knowledge of the Scottish naturalist's observation. Nitrogen ofifers 

 little encouragement to the experimenter. If he collects a jar of the 

 gas and introduces a candle in it. the candle goes out. If he put a 

 mouse there, the mouse dies. Scheele was the first then who de- 

 monstrated, by analysis and synthesis, that the air consists mainly 

 of two gases, one supporting combustion and the other prevent- 

 ing it. 



The year 1775 was as stirring for Scheele as it was for the English 

 colonies in America. The price of potash salts was increasing enor- 

 mously, and attempts were made to produce the carbonates from 

 common salt. The French Academy of Sciences ofifered 2,400 livres 

 to any one who would succeed in converting salt to soda. Scheele 



