37 
of Edinburgh, Session 1880-81. 
the figures correspond, while in Nos. 11 and 12 the percentage of 
silver is far above that required for the triargentic salt. Wacken- 
roder* appears to have been the first to afford the information that 
a tribasic meconate of silver is produced by precipitation, when the 
ammonium meconate is used, and that the same salt is formed by 
boiling the diargentic meconate with water. These statements., 
though generally accepted as correct,, are not borne out by anything 
I have observed. Doubtless, if in boiling the meconate of silver 
with water the operation be stopped at a certain point, the product 
will have apparently the composition of the triargentic salt ; but 
then, if the boiling be continued, the percentage of silver increases, 
until probably there is nothing but oxide of silver left. There is 
therefore no evidence that a tribasic meconate has been prepared, 
and we are not, so far as I can see, in possession of any information 
which should lead us to suppose that meconie acid is tribasic. 
3. On the Crystallization of Silica from Fused Metals. By 
K. Sydney Marsden, D.Sc., F.B.S.E., F. Inst. Cliem., &a 
The crystallization of silica from fused metals, although at first 
sight appearing to be of little importance, nevertheless presents 
some features of peculiar interest. It also constitutes a field almost 
entirely new to the investigator, though the subject is one which, 
from a technical point of view, may prove to be of very consider- 
able importance. 
I have therefore undertaken the examination of some of the facts 
relating to this subject — at first more particularly inquiring into the 
nature of the change which occurs when silica itself is kept at a 
high temperature for a number of hours and subsequently submitted 
to a process of very slow cooling. 
The substance which formed the basis of these operations, and in 
which the changes hereafter mentioned were noticed, consisted of 
several Berlin porcelain crucibles, in which, in the course of some 
other experiments, I had reason to keep metallic silver and amor- 
phous carbon at a temperature considerably above the melting- 
point of the former, for a number of hours, and subsequently 
* Gmelin’s Handbook, xii. 430. 
