Oxidation. 
It may give 
rise to light 
or not. 
6 ON THE PLACE OF FISH IN 
Without Oxygen animal life as it now exists on 
this planet would be impossible, and every one, 
whether they know the fact or not, has had life 
maintained by Oxygen from the earliest moments of 
their existence. 
The word that is used to express union with Oxygen 
is OXIDATION. It is the oxidation of the elements 
of which coal is composed that gives rise to the heat 
and light of a fire. Oxidation appears to always 
give rise to heat. In some cases the heat is so 
slight it requires delicate instruments to detect it, in 
some it can be readily observed, while in many cases 
it is so great it gives rise to light. Very familiar 
cases of oxidation are those which give rise to much 
light—the oxidation for example which occurs in 
lamps and candles. Here the substances oxidized 
are purposely selected in consequence of their rapid 
oxidation producing light. 
This depends upon the vate of oxidation. Slow 
oxidation frequently accumulates so much heat that 
after a while light and flame are produced, anid this 
not unfrequently occurs in places, as for example in 
hay-ricks and cotton factories, where such rapid 
oxidation is not desired. 
Because the word “ burning” is so commonly used 
for those cases of oxidation which give rise to light, 
some writers, for the sake of avoiding the unfamiliar 
word, speak of all oxidation as “burning.” So long 
as a definite meaning is kept to, it is entirely a ques- 
tion of words, but if “burning” is used instead of 
“oxidation,” then it must be applied to such a case 
as the oxidation of iron, which is commonly called 
“rusting,” and to similar cases where oxidation does not 
