Chapter I. 
THEORIES OF OXIDATION. 
In the period which elapsed between the classic researches of 
Lavoisier on Combustion (1774-1785) and the discovery of ozone 
Schoenbein in 1840, a number of interesting and important obser- 
vations had accumulated in the literature concerning the influence 
exerted by one substance on the oxidation of another by air or oxygen. 
Thus in 1806 Desormes and Clement ( 137 ) pointed out that nitric acid 
is not the principal agent concerned in the complete oxidation of the 
sulfur in the leaden-chamber process for the manufacture of sul- 
furic acid, but its “base,” nitric oxide ( le gaz nitreux), which takes 
oxygen from atmospheric air in order to offer it to the sulfurous 
acid in a condition capable of accomplishing its oxidation. A few 
years later it was observed by Vogel ( 443 ) that hydrogen and oxygen 
combine at low temperatures under the influence of charcoal. Then 
followed the numerous and interesting observations by Sir Humphrey 
Davy ( 134 ), Edmund Davy ( 132 ~ 133 ) ; Erman ( 167 ), Pleischl ( 328 ), and 
others on the remarkable power of platinum and other metals of the 
platinum group, such as iridium, osmium, and palladium, to effect 
the slow combustion, or under certain conditions even the actual 
ignition, of combustible gases such as hydrogen, carbon monoxide, 
etc., in an atmosphere containing oxygen, and the rapid conversion 
of alcohol into acetic acid, observations which culminated in Davy’s 
lamp without flame (see Erman 167 ), Doebereiner’s lamp ( 141 ), and the 
rapid method for the production of acetic acid. 
The effect of various substances on the oxidation of combustible 
gases and vapors was also exhaustively investigated by Dulong and 
Thenard ( 151 - 152 ) ? with the result that various metals, such as iridium, 
palladium, rhodium, gold, silver, mercury, nickel, cobalt, and iron, in 
spongy or pulverulent form, were found to accomplish the same 
changes as platinum, and that to a degree at least such changes can 
also be brought about by certain nonmetallic substances, such as car- 
bon, pumice stone, porcelain, glass, and quartz crystals, at tempera- 
tures under 350° C., while salt, fluorspar, and marble did not appear 
to act to a sensible extent within these limits. These changes, they 
concluded, could not be ascribed entirely to electrical phenomena, as 
was at first supposed, and the} T explained them on the assumption of 
the condensation of large volumes of gas on the surface of the sub- 
( 9 ) 
