292 On the Artificial Formation of Minerals. 
up of fragments of organized beings, should long ago have 
satisfied the most sceptical that both animal and vegetable 
life was as active and profusely scattered upon the whole 
globe, at all times and during all geological periods, as it is 
now. No coral reef in the Pacific contains a larger amount 
of organic debris than some of the limestone deposits of the 
tertiary, of the cretaceous, or of the oolitic, nay, even of the 
paleozoic period, and the whole vegetable carpet covering the 
present surface of the globe, even if we were to consider only 
the most luxurious vegetation of the tropics, and leave en- 
tirely out of consideration the whole expanse of the ocean, as 
well as those tracts of land where under less favourable cir- 
cumstances the growth of plants is more reduced, would not 
form one single seam of workable coal to be compared to the 
many thick beds contained in the rocks of the Carboniferous 
period alone. 
On the Artificial Formation of Minerals. 
There are a number of minerals, with regard to which 
most mineralogists, geologists, and chemists, are of opinion 
that they can only have been formed by crystallization from 
a melted mass. A considerable portion of these minerals 
are, however, infusible ; or, at least, require such a temper- 
ature for fusion, as cannot reasonably be supposed to have 
been concerned in the formation of the rocks in which they 
occur. Some of these compounds, on the other hand, may 
be easily formed by fusion at a moderate temperature. Thus, 
more than thirty years since, Mitscherlich showed that augite 
or pyroxene—one of the most widely distributed minerals— 
may be formed by melting together silica and various bases of 
the magnesian series, in such proportions that the oxygen of 
the acid amounts to twice as much as that of the bases. 
He also showed that this mineral substance, with its proper 
form, occurs in the slags obtained in metallurgical opera-~ 
tions ; and the subsequent examination of slags has led to the 
recognition in them of several other compounds identical 
with, or analogous to, native minerals. 
Nevertheless, there are a great number of minerals, in 
