390 Chronicles of Science. [July, 
was then proceeded with, and after the usual votes of thanks the 
meeting adjourned. 
On Thursday, April 2nd, the first paper read was one by 
Messrs. Perkin and Duppa, “On the Constitution of Glyoxylic 
Acid.” This was followed by a very long and highly theoretical one 
by Dr. Odling, “On a Glyoxylic Amide.” Mr. W. Chandler Roberts 
then read a note “On the Occurrence of Organic Appearances in 
Colloid Silica obtained by Dialysis.” The interesting observations 
which formed the subject of this paper were elucidated by a series 
of specimens, both of natural and artificial origin, the structures of 
which were demonstrated by the aid of a microscope and illustrative 
drawings. In experimenting upon somewhat large quantities of 
soluble silicic acid prepared in Graham’s dialyser, a portion of the 
liquid product was evaporated slowly in air to compare with the 
forms of hydrous silica left by a more rapid operation conducted in 
vacuo. All the specimens of jelly dried in air exhibited dendritic 
forms, varying in size from 0:2 to 0°5 mm.; these were at first 
supposed to afford indications of the passage of colloid into erystal- 
loid silica, but when magnified 90 linear they appeared as radiating 
fibres, and upon being further magnified 700 times, each fibre 
resolved itself into a collection of elongated headed cells, with 
clusters of circular cells at intervals. Such a structure would 
indicate a vegetable growth, and the author concludes that the 
markings, which are similar to those seen in moss agates and 
Mocha stones, are due to the growth of fungi or mildew in the 
partially solidified jelly. The spores of organic life were probably 
derived from the air, since no evidence of similar structure was 
visible in the specimens of hydrous silica obtained in the desiccator. 
These last-named productions were very like the opal from Zimapan, 
but contained 21:4 per cent. of water. Dr. Bence Jones com- 
municated the next paper, in which he demonstrated the “Solu- 
bility of Xanthin (Uric Oxide) in Dilute Hydrochloric Acid.” This 
was followed by a continuation of Professor A. H. Church’s “ Re- 
searches on New and Rare Cornish Minerals,” in which the author 
corrected the hitherto-received formula for the mineral Cornwallite, 
showing it to consist of arseniate and hydrate of copper, with a 
small proportion of phosphate. 
At the meeting on the 16th of April, Professor Guthrie de- 
scribed and exhibited an ¢mproved Voltastat, by means of which 
the current of a galvanic battery could be maintained perfectly 
constant and regular by a self-acting arrangement. A paper “On 
Graphic Formule,” by the same author, followed, in which he 
described a new system, founded on the same general principle as 
that of Dr. W. Crum Brown, but which would, in the words of the 
author, “ serve to illustrate the molecular constitution of compound 
bodies from a somewhat different perspective.” Instead of initial 
