Royal Society. 59 
C® H? NO*=2C0? + C* H7 N 
Alanine. - Ethylamine. 
C4 H7 N+ 2NO%= (C* H® O NO*) + N?4.2HO 
Ethylamine. Nitrous Nitrite of 
acid. zthyle. 
C* H® ONO? + 6(KSHS) =C* H® O, HO + NH?+ 2HO + 6KS?, 
Nitriteof | Sulphydrate of Alcohol. 
zthyle. sulphide of 
potassium. 
VII. Proceedings of Learned Societies. 
ROYAL SOCIETY. 
[Continued from vol. xiii. p. 528. ] 
December 11, 1856.—General Sabine, R.A., V.P. and Treasurer, 
in the Chair 
‘THE following communications were read :— 
- “On Practical Methods for rapid Signalling by the Electric 
Telegraph.’ By Prof. W. Thomson, F.R.S. 
I am at present engaged in working out various practical applica- 
tions of the formule communicated some time ago in a short article 
on the “Theory of the Electric Telegraph” (Proceedings, May 17, 
1855), and I hope to be able very soon to lay the results in full 
before the Royal Society. In the mean time, as the project of an 
Atlantic Telegraph is at this moment exciting much interest, I shall 
explain shortly a telegraphic system to which, in the course of this 
investigation, I have been led, as likely to give nearly the same 
rapidity of utterance by a submarine one-wire cable of ordinary 
lateral dimensions between Ireland and Newfoundland, as is attained 
on short air or submarine lines by telegraphic systems in actual use. 
Every system of working the electric telegraph must comprehend 
(1) a plan of operating at one extremity, (2) a plan of observing at 
the other, and (3) a code of letter-signals. These three parts of the 
system which I propose will be explained in order,—I. for long sub- 
marine lines, and II. for air or short submarine lines. 
I. Proposed telegraphic system for long submarine lines. 
1. Plan of operating.—This consists in applying a regulated gal- 
vanic battery to give, during a limited time, a definite variation of 
electric potential determined by theory, so as to fulfil the condition 
of producing an electric effect at the other extremity, which, after 
first becoming sensible, rises very rapidly to a maximum, then sinks 
as rapidly till it becomes again, and continues, insensible. 
The principle followed is that pointed out by Fourier, by which 
we see, that, when the wire is left with both ends uninsulated after 
any electrical operations whatever have been performed upon it, the 
distribution of electric potential through it will very quickly be 
