308 Biography of Berzelius. 
The great authority of Berzelius, and the soundness with which 
he carried out his refutation of all the evidence brought forward 
in favor of the new theory, were the reasons why many chemists, 
especially in Germany, did not adopt Davy’s view of the nature 
of chlorine. 
The immediate cause that led Berzelius to undertake the inves- 
tigation of the cyanids of iron was evident, viz., he expected to 
find in them a more complex radical (united with oxygen form- 
ing an acid) associated with an oxygen base, and similar to that 
which he assumed to exist in muriates. It cannot be disputed 
genous salts, and especially as several metallic cyanids, such as 
eyanid of mercury or silver, correspond so completely with the 
analogous chlorine compounds, he was of opinion that if he could 
by this investigation detect oxygen in the ferrocyanic compounds, 
it would be a strong proof of its presence in muriates likewise, 
and, consequently, evidence in favor of the old theory of the 
nature of chlorine. 
However, the result of these investigations was the opposite of 
that which he expected, and thus the main argument against the 
new doctrine of the nature of chlorine fell to the ground. n 
other reasons for the greater probability of the new theory were 
from time to time discovered, Berzelius adopted it with the most 
amiable candor, and relinquished the old theory which he had so 
long and so ably defended. 
ne, among the reasons was, as I know, the following :— 
Immediately after Berzelius’s investigations on the cyanids of 
iron, Leopold Gmelin obtained the interesting red double salt 
of cyanid of potassium and cyanid of iron, which is anhydrous 
and contains no oxygen. The red color of peroxyd of iron, 
which is more or less communicated to all its salts except the 
neutral ones, was to Berzelius an additional reason for regarding 
the red perchlorid of iron as an actual salt with an oxygenous 
base ; and, as in the salt obtained by Gmelin, notwithstanding its 
red color, the iron was not in the state of oxyd, but directly com- 
bined with cyanogen, (one double atom of iron with three double 
atoms of cyanogen,) Berzelius saw that it was probable that the 
red color of iron compounds was not owing alone to the presence 
in them of peroxyd, but was also common to those in which one 
double atom of iron is combined with three double atoms of 
chlorine or cyanogen. eas 
Another main inducement to adopt the new theory of the 
nature of chlorine, consisted in the results which he derived in 
favor of it from his subsequent comprehensive res pon al- 
kaline sulphurets. According to Berthollet’s investigations, these 
