324 * Scientific Intelligence. [APRIL, 
of the nervous influence and galvanism, or that there is a power 
different from the nervous influence yet capable of performing its 
most complicated functions, a supposition, 1 think, much harder to 
be granted than the other. 
Both this experiment, and the experiments on rabbits, relating 
to the same subject, were made in the presence of several medical 
Gentlemen, who expressed their entire satisfaction in the result. 
- I remain, Sir, your obedient humble servant, 
C. P. Witson Puitip. 
XIII. New Spectacle Glasses. 
(To Dr. Thomson.) 
SIR, March 6, 1816, 
I have been informed that the French of late have been trying 
plano-cylindrical glasses with the plane surfaces in contact, and the 
axes at right angles. These have been used as lenses; and it is said 
that Dr. Wollaston is in possession of one of this construction. Any 
information which you can give your readers on this subject cannot 
fail to be interesting to them. 
During the cold weather of January, 1814, a bubble of air (like 
that which you described a few months ago) was discharged from 
the spirits of wine of one of Six’s thermometers. It measured 
16-9°, and was reduced by the application of heat, although it was 
not then known that any such process had been used with success, 
The spectacle glasses alluded to by my correspondent consist of 
two segments of cylinders applied at right angles to each other. The 
object, I conceive, is to destroy the effect of spherical aberration. 
As far as I have been able to learn, this species of lens has not been 
fcund to answer well in this country, though I am not quite sure 
that they have undergone a fair trial. 
XIV. Urie Acid. 
Gay-Lussac mixed uric acid with 20 times its weight of peroxide 
of copper, put the mixture into a glass tube, and covered it with a 
quantity of copper filings. ‘The copper filings, being heated to a 
dull red heat, heat was applied to the mixture. The gas which came 
over was composed of 0°69 carbonic acid and 0°31 azote. He 
conceives that the bulk of the “carbonic acid would have been 
exactly double that of the azote had it not been for the formation of 
a little carbonate of ammonia. Hence uric acid contains two atoms 
of carbon and one atom of azote. This is the same proportion as 
exists in cyanogen. (Ann. de Chim. vol. xevi. p. 53.) To what, 
then, are we to ascribe the difference between hydro-cyanic acid and 
uric acid? Does uric acid contain an atom of oxygen combined to 
cyanogen, while hydro-cyanic acid consists of the same base united 
to an atom of hydrogen? i 
