PROGRESS IN CHEMISTRY. 235 



carbon, sulphur, phosphorus, and similar bodies, and not the products 

 of their oxidation. 



The discovery that air is, in the main, a mixture of nitrogen, an 

 inert gas. and oxygen, an active one, together with a small proportion 

 of carl)onic ''acid'' (or, as it is now termed, anhydride)— a discovery 

 perfected by Rutherford, Black, and Cavendish — and that water is a 

 compound with oxygen of hydrogen, previously known as inflammable 

 air, ))y Cavendish and by Watt, tinally overthrew the theory of phlo- 

 giston, but at the beginning of this century it still lingered on, and was 

 defended by Priestley until his death in 1804. Such, in brief, was the 

 condition of chemical thought in the year 1800. Scheele had died in 

 1786, at the early age of -ll:; Lavoisier was one of the victims of the 

 French Revolution, having been guillotined in 1794; Cavendish had 

 ceased to work at chemical problems and was devoting his extraordi- 

 narv abilities to physical problems of the highest importance, while liv- 

 ing the life of an eccentric recluse; and Priestley, driven Iw religious 

 persecution from England to the more tolerant shores of America, 

 was enjoying a peaceful old age, enlivened by occasional incursions 

 into th(» region of sectarian controvers}'. 



FIRST STRIKING^ DISCOVERT OF THE CENTURY. 



The first striking discovery of our century was that of the com- 

 pound nature of alkalies and of the alkaline earths. This discoveiy 

 was made by Humphry Davy. Born in Cornwall in 1778, he began 

 the study of chemistry, self-taught, in 1796, and in 1799 he became 

 director of the Pneumatic Institution, an undertaking founded 1)}' 

 Dr. Beddoes at Bristol for the purpose of experiments on the curative 

 efl'ects of gases in general. Here he at once made his mark by the 

 disco\ery of the remarkable properties of *• laughing gas,'' or nitrous 

 oxide. At the same time he constructed a galvanic battery, and began 

 to pei'form experiments with it in attempting to decompose chemical 

 compounds b}" its means. In 1801 Davy was appointed professor of 

 chemistry at the Royal Institution, a society or club which had been 

 founded a few years previoush' by Benjamin Thomson, Count Rum- 

 ford, for the purpose of instructing and amusing its members with 

 recent discoveries in chemistiy and natural philosophy. In 180T Davy 

 applied his galvanic battery to the decomposition of damp caustic 

 potash and soda, using platinum poles. He was rewarded by seeing 

 globules of metal, resembling mercury in appearance, at the negative 

 pole, and he subsequently proved that these globules, when burned, 

 reproduced the alkali fiom which they had been derived. They also 

 combined with "oxymuriatic acid," as chlorine (discovered by Scheele) 

 was then termed, forming ordinary salt, if sodium be employed, and 

 the analogous salt, ''muriate of potash," if the allied metal, potassium, 

 were sul)jected to combustion. By using mercury as the negative 



