1879 -] 
Proceedings of Societies. 
815 
Capt. Armstrong exhibited a standard Daniell cell formed of a 
porcelain vessel with a porous partition dividing it into two com- 
partments. In one the zinc plate was immersed in a solution of 
sulphate of zinc ; in the other the copper plate in a solution of 
sulphate of copper. To use the cell as a standard, it was only 
necessary to connedt the two liquids by a cotton string moistened 
with water. This arrangement prevented mixing of the liquids, 
as the string could be withdrawn after use. The resistance was 
high, but it was a constant standard of electromotive force. 
Prof. Guthrie mentioned that Prof. Pirani, of Melbourne, in a 
letter to him, had signalled the fadt that when a dilute acid was 
being eledtrolysed, the positive eledtrode, if made of iron, be- 
came incandescent below the surface of the liquid. Prof. Guthrie 
had found this to be true not only for iron, but for other metals, 
and that it could hardly be due to oxidation, because it took 
place not only at the cathode or positive eledtrode, where oxygen 
was evolved, but also at the anode, where hydrogen was evolved. 
The incandescence appeared to him to be due rather to resist- 
ance. The author exhibited his experimental results, which he 
did not doubt had already been obtained by Prof. Pirani himself. 
The positive eledtrode when immersed in the eledtrolyte was 
seen to get red-hot and to wobble about. As the liquid heated 
the red glow became fainter. The negative eledtrode, on the 
other hand, emitted a bright light, accompanied by a sputtering 
noise. The light was tinged with the characteristic colour of 
the flame of the metal of which it was composed ; in the case of 
a copper eledtrode, for example, it was greenish. These effedts 
were shown by Prof. Guthrie with iron, copper, and platinum 
eledtrodes, in dilute sulphuric and dilute nitric acids. 
November 22, 1879. — Prof. W. G. Adams in the chair. 
Prof. Guthrie exhibited a new Image Retention Photometer, 
and demonstrated its adtion to the meeting. 
Dr. Shettle, of Reading, read a paper on the “ Influence of 
Heat upon certain forms of Induction Coils, considered more 
especially in relation to the Indudtive Power which the Blood 
exercises on the Various Structures of the Body. The author 
found that when a copper and a zinc wire were insulated from 
each other by parchment-paper and paraffined silk, and wound 
in close proximity to each other, an (induced) current was indi- 
cated on a galvanometer whose terminals were connected to the 
neighbouring ends of the zinc and copper wires respectively, the 
other ends being left free. When the latter were connected 
across the defledtion was nil. On raising the temperature of the 
two wires, by causing hot water to flow inside the coil into which 
they were wound, the defledtion was largely increased. These 
experiments led Dr. Shettle to imagine that there is a similar 
adtion in the animal body. The heart is made up of nerves and 
muscular fibres winding spirally, and some of these wind round 
