106 REPORT—1845. 
from a piece of pure graphite, between the thermo-electric agent and its 
rheophore. The graphite acts but very feebly by its contact with heteroge- 
neous substances, and at the same time proves an excellent conductor for 
electricity excited in any other manner. It is desirable that other means may 
be found to obviate the impediments resulting from the extreme sensibility of 
the apparatus which must be necessarily employed, as a minute absolute in- 
tensity is a characteristic feature of all tribo-electric actions, and can alone 
explain the reason of their having been so long either unnoticed or errone- 
ously estimated. When, by immersion in a vessel of warm water, the tempe- 
rature of a bar of bismuth and of another of antimony is elevated to upwards 
of 45° R., they will give by this contact a very strong eastward deviation, but 
the friction will not cause it to increase any more in asensible degree. When, 
on the contrary, the same two bars are greatly refrigerated by being plunged 
in triturated ice, their contact gives a strong negative or western deviation, but 
the friction in this case, far from inverting this effect, is not even able to di- 
minish it in any material degree. The calorific increments produced by fric- 
tion are in themselves very feeble; the tribothermic multiplicator acts, in 
respect to them, as a microscopic apparatus ; but the fact that its indications 
are circumscribed within certain limits, and becomes insensible when these 
limits are passed, is of striking importance. We need only to ascertain by 
very careful experiments the degrees of heat and of refrigeration given to the 
metals, by which their friction loses its influence on the needle, in order to 
obtain for a scale of tribothermic production of heat, two fixed points which 
can be reproduced in any instance, in exactly the same manner as the fixed 
terms of our ordinary thermometer. The philosophers who may apply them- 
selves to tribothermic experiments, will not fail to meet with the paradox of two 
electric currents acting simultaneously in contrary directions. In the frequent 
cases where the contact produces a deviation of the needle in a certain sense 
and the friction in the contrary one, we can so modify these actions that the 
needle remains in equilibrium in an intermediate position, obeying the two 
currents that travel along the same wire in contrary directions. As to the 
obscure question of the relation between the direction in which the heat moves, 
according to the received terminology of the thermo-electric phenomena, and 
the direction in which electricity proceeds, it is not impossible, although 
highly improbable, that tribothermo-electric researches may throw some 
light upon it. The following Table presents the state of this question :— 
Being at the temperature 
Being heated, of the surrounding space. 
p ‘ The contact gives an eastern deviation. 
totes) ae 4 Beat loses heat and gains electricity. 
? ‘ The contact gives an eastern deviation. 
eee “eign ‘Ban gains heat and gains electricity. 
Being at the t tur 
Being refrigerated. of the sitergundirg spdde, ati) 
Bismuth h eilinan The contact gives a western deviation. 
Lem tr Y-+ ) Bismuth gains heat and /oses electricity. 
. : The contact gives a western deviation. 
Saou | ee 1 Bismoth loses heat and loses electricity. 
The friction increases the eastern deviations and changes all the western 
into eastern ones, that is to say, that bismuth becomes equally positive by an 
increase or a diminution of heat. May it be inferred that heat when nascent 
by the act of friction has a property specifically different from that of heat 
residing previously in a metal? Are we perhaps on the eve of finding at 
length something analogous to the brilliant discovery of Peltier, that gal- 
vanic electricity produces heat in proceeding from antimony to bismuth, 
