Str Humphry Davy. 23] 
the Se ae of chemistry to be remodelled, and its nomenclature 
to be chang Lavoisier’s definition of combustion, “the combin- 
ation of oxyaen with a combustible base,” could no longer’ be admit- 
ted, but a new classification was to be instituted, comprehending not 
oniy those cases of combustion which depend on the agency of oxy- 
gen, but those also which depend on the agency of chlorine, and 
other analogous bodies which might afterwards be discovered.* 
Now combustion and acidification are processes of ‘such extent, 
and ‘are concerned in so many of the chemical changes which bodies 
undergo, that any new theory which alters the explanation of these 
phenomena, affects in a great degree the whole philosophy of chem- 
istty. It is by the relations which a body sustains to chemical agents, 
and especially to caloric and oxygen, that its chemical nature is de- 
termined.’ Hence, a complete history of the properties of almost 
any" substance, in all its relations, involves an application of nearly alll 
“the leading principles of the science. Scheele wrote an essay on 
manganese, in which, after the labor of three years, he unfolded 
most of the properties of that substance, many of which had been 
before unknown. “During his experiments on manganese, he discov- 
ered both oxygen and chlorine, and Jearned the most important prop- 
erties of these extensive agents. The selection of manganese, as a 
subject for experimental research, was in some’ Tespects fortunate ; 
but had Scheele investigated the properties of several other substan- 
ces, with the same persevering attention and singular acuteness, he 
Would have made the same discoveries. ‘In like manner, to ‘seitle all 
the relations of chlorine to various chentical agents, must eam 
application of nearly all the teading’ principles of chemical science: 
« Ang it be admitted that the views of Sir Humphry Davy reget 
rine , 
tion, yet it must be admitted also that uavoisier reasoned logically from aieieaem, 
In a great multitude of cases of combustion and acidification which fell under the 
examination of Lavoisier, oxygen was proved to be present, nor was any case of ei- 
of tr 
Principles of induction, Lavoisier was entitled to lay it down asa a general law*—“In 
every case of combustion, ie combines with the ams body.” ay subse- 
quent discoveries have shew 
ucing combustion, and in eens acids. Fidadets oie ies; which before stood ne ~ 
head of a genus, now takes its = at cig “eo of . poe =e ‘ 
4 certain number of cases of combu 
cneeles, and iodine at the head of sees and all of them are to be “classed under 
mbustion. 
yd 
cause ur 
Se Ser 
as *Se0 Newtaes Risles or philodophteltig. 
