148 Proceedings of the Royal Society 
The empty part of the wider limb communicates, through F, 
with the gas-supply, through G- with the gas-lamp serving to 
heat the air-bath; and the quantity of mercury is adjusted so 
that, when the gas is at the lowest pressure which, in the course 
of the experiment, it is likely to “assume, the mercurial index 
in C occupies a certain convenient position a. 
The manometer is connected with a constant battery (the circuit 
of which includes an electro-magnetic arrangement for opening or 
shutting the gas-tap), in such a manner that, as soon as, through 
ah increase of pressure in E, the index in C travels ever so little 
towards the right of a, the current is closed, and the gas cut off. 
The following Gentlemen were elected Fellows of the 
Society : — 
John Macmillan, M.A. 
John Gibson Cazenove, D.D. 
The following Gentlemen were elected Honorary Fellows 
of the Society : — 
1. Foreign Honorary. 
Carl Ludwig, Leipzig. 
Ferdinand de Lesseps, Paris. 
2. British Honorary. 
Henry John Stephen Smith, Oxford. 
Thomas Henry Huxley, London. 
Thomas Romney Robinson, D.D., Armagh. 
Monday, 17 th April 1876. 
Professor FLEEMJNG JENKIN in the Chair. 
The following Communications were read : — 
1. On an Improved Form of Galvanic Battery. By J. 
Cook, Esq. Communicated by Professor Tail. 
I wish to direct attention to a simple improvement on battery 
cells, whereby porous cells are dispensed with, and the incon- 
veniences of gravity batteries avoided. 
