184 Biography of Berzelius. 
without causing a sensible alteration in the substance. If it ever 
happens,—continues Mohs,—that a branch of natural history as 
mineralogy, employs such characters in its method as these last 
mentioned, it then exceeds its legitimate bounds, becomes ef- 
tangled with other sciences, and hampered with all those difficul- 
ties of which mineralogy has long been a warning example. 
Berzelius criticised this argument with justice. He declared 
that it seemed to him the same as if a man who is stumbling m 
the dark, should hesitate to make use of a light, because he would 
then see more than he required, and because he hoped to find 
his way without it. 
In order to appreciate fully the great merit of Berzelius, in put- 
ting forward his mineral system, it is only necessary to call t 
mind how great was the chaos in mineralogy before his time, and 
especially with regard to the classification of the numerous coml- 
pounds of silica. Although both Débereiner and Smithson com- 
menced to regard silica as an acid, at about the same time as 
Berzelius, still it was he who first made an extended application 
is View, in the new mineral system which he proposed, by 
means of which siliceous minerals were included under the h 
of saline compounds, and the correct conception of their compo 
sition first rendered possible. 
he greater number of natural compounds of silica are double 
salts; and observing the great diversity among them, Berzelius 
raised the question, as to whether it was probable that the indi- 
vidual members of such double salts were different stages of sat- 
uration. As he had previously assumed only the most simple re- 
lations in chemical compounds, he was at first led to infer upot 
theoretical grounds, that the existence of dissimilar stages of sat- 
uration in the double salts of silica, was less probable, especially 
ne had never met with any similar phenomena in his investl- 
gations of the double salts of other acids. Nevertheless, he su 
formule which expressed their composition. But as Berzelius 
was long doubtful how many atoms of oxygen he should assume 
in silica, and even when he afterwards decided for three atoms, did 
not regard this assumption as perfectly certain, he introduced more 
simple formule for siliceous compounds, which he termed mit- 
eralogical, and distinguished from the chemical formule by th® 
printers’ type employed. et 
ae 
See 
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