6 
Cuvier’s Historical Ehge of Werner. 
ing power is such, that they constrain very considerable quan- 
tities of different bodies to accommodate themselves to their 
form ; and it has long been observed in nature, that crystals 
in all respects are alike ; those of sparry iron, for instance, may 
contain more or less of iron, or more or less of lime, as there 
may be in two animals of the same species a greater or less 
quantity of fat, of gelatine, or of the earth of bones. 
In mineralogy, then, crystallization ought to be the funda- 
mental principle of the species, of the visible species. But in 
an immense majority of minerals, the crystalline form is not 
apparent, and in these cases composition cannot give us this 
principle, for the composition of such bodies Varies still more 
than that of crystals, and foreign mixtures more easily corrupt 
their purity. 
What then is to be done We must have recourse to those 
properties which are most nearly allied to the fundamental 
principle, — to the cleavage, which is but one of its phenomena, 
to the fracture, to the hardness, to the lustre, to the effect of 
the body on the touch, which are its more or less immediate 
consequences. 
This is what Werner has done, not perhaps that he has 
exactly proceeded upon these reasonings, but he has done it by 
that sort of delicate instinct which was the peculiar character of 
his genius. He has the air of considering the identical com- 
position of the molecules as the principle of species, and the 
point from which he sets out, — perhaps because he really be- 
lieved himself to have set out from thence ; but he never ac- 
tually applies this principle, except when it is in agreement 
with the external qualities, and in all cases it is upon these 
properties that he has founded his distributions, leaving analy- 
sis to reconcile itself to them as it may. All the unctuous 
stones, for instance, are classed in the Magnesian Order, al- 
though many of them contain more alumina or silica, than mag- 
nesia. He carried this rule so far, that he always persisted in 
leaving the diamond among the siliceous stones, notwithstand- 
ing the incontrovertible experiments which prove that this gem 
is only a crystallization of carbon. What is more remarkable, 
is, that among all these external properties, the one on which 
