320 Intelligence and Miscellaneous Articles. 
that thermal and thermo-electric effects generally accompany such a 
passage. To get rid of this source of uncertainty, I have repeated 
Ampére’s experiment in a form which excludes it entirely. In this 
form of the experiment the polar conductors and the float form one 
continuous metallic mass with the mercury in the troughs,—the float 
being formed of glass tube filled with mercury, with its extremities 
slightly curved downwards so as nearly to dip under the surface of 
the fluid, and the wires from the battery being plunged into the 
upturned outward extremities of two glass tubes, which are pushed 
through the ends of the troughs so as to project an inch or two in- 
wards under the surface of the mercury. A little practice is requisite 
to success in filling the float and immersing it in the troughs with- 
out admitting a bubble of air. This float, being heavier than the 
ordinary copper wire, plunges deeper in the fluid, and encounters 
more resistance to its motion; but with two small Grove’s cells only, 
Ampére’s result was easily reproduced, even when the extremities 
of the float rested in contact with those of the polar tubes before the 
circuit was completed. It is obvious that here no thermo-electric 
effects can be produced in the mercury; and I have satisfied myself 
that the motion commences before the passage of the current can 
have sensibly heated the fluid in the tubes. 
The other class of objections to Ampére’s conclusion from this 
experiment, depending on the spreading of the current in the mer- 
cury of the troughs, is of course not met by this modification. I 
have made several experiments with a view to obviate this also; but 
my time has been so much occupied that I have not been able as yet 
to put them in a form suitable for communication to this Society.— 
From the Proceedings of the Royal Society of Edinburgh, vol. iv. 
NOTE RESPECTING OZONE. 
In the Philosophical Magazine, May 1860, page 403, is a short 
account of ‘‘ the production of Ozone by means of a Platinum Wire 
made incandescent by an Electric Current,” by M. Le Roux, which 
has just recalled to my memory the following fact. 
I have frequently observed that a coil of platinum wire heated to 
whiteness in a strong jet of purified hydrogen, and then removed from 
the jet, imparted a feeble ozone-like odour to the ascending stream 
of hot air above the wire as long as the wire remained nearly white- 
hot, and ceased to impart this odour at a somewhat lower tempe- 
rature. 
G. Gorr. 
Birmingham. 
