354 On the Influence of Temperature, 8c. [May, 
of particles of the muriatic acid from the antimony, which would 
be requisite for their chemical affinity; say that one particle of 
antimony unites with two of muriatic acid, the water prevents these 
numbers of particles coming together. ’ 
ARTICLE V. 
Facts relative to the Influence of Temperature, Mechanical Pres- 
sure, and Humidity, on the Intensity of the Electric Power, and. 
on changing the Nature of the Electricity. By J. P. Dessaignes.* 
(Read to the French Academy of Sciences, June 24, 1816.) 
I HAVE the honour of presenting to the Academy some new 
facts tending to discover the kind of action which temperature, 
mechanical action, and humidity, exercise on the electric power, 
and the manner in which the electricity changes its nature. The 
experiment of Bergman, of two skeins of silk rubbed together, 
whose electricity varies according to the kind of friction, is merely 
an isolated fact, incapable of establishing a principle, because it 
does not lead to any general consequence. It constitutes a branch 
which requires to be united to its trunk. If at all times a new fact, 
though totally unconnected, has excited some interest, surely we 
cannot refuse our attention to the family to which it belongs. 
First Fact. —1. When a glass rod is naturally electric in mercury, 
if we plunge it into mercury exposed to the external air when the 
weather is dry and cold, and then bring it near an electric needle, 
we find it four times more electric than mercury at the common 
temperature of a close room. ‘To produce this effect, it is not 
necessary to wait till the mercury be cooled. It is sufficient to 
carry it into the open air, and then to plunge the glass rod into it 
immediately. The electric power increases usually on the first im- 
pression of the cold. When the rod is naturally unexcitable in the 
mercury at the temperature of the apartment, and the external air 
is a little cooling, it is sufficient, in order to render it electric, to 
carry the mercury out of doors, and to plunge the rod into it. 
What I have just said-of mercury is common to all the metals. 
2. Glass is much less sensible to the impression of cold than 
mercury. However, if we plunge the rod once into mercury ex- 
posed to the open air during a cold north wind, and then immerge 
it into mercury of the temperature of the apartment, it comes out 
more electrical than before. When it is naturally unexcitable in 
mercury, if we cool it gradually with ether, it becomes susceptible 
of acquiring a very weak electricity, but it becomes again inex- 
citable when it recovers the temperature of the room. 
* Translated from the Ann, de Chim, et Phys. ii. 59. 
