1819.] Sur ?’Identité des Forces Chimiques et Electriques. 457 
chemical forces of combustibility and burning, of which he 
treated in the second chapter. When two metals differing in 
their combustibility are placed in contact, and the circle com- 
pleted by a quantity of water, the burning force of the water is 
attracted by the force of combustibility of the most combustible 
metal; while the force of combustibility of that metal repels the 
force of combustibility of the water, which force is attracted 
towards the least combustible metal, which contains an excess 
of burning force. Hence a current of the burning force of the 
water passes through the liquid towards the most combustible 
metal ; while an opposite current of the force of combustibility 
passes through the same liquid towards the least combustible 
metal. Hence the hydrogen of the water is attracted to the 
least combustible metal, and the oxygen to the most combustible 
metal. The hydrogen, when it comes in contact with the least 
combustible metal, makes its escape im the form of gas ; but the 
oxygen usually combines with the most combustible metal. 
Whatever promotes the action of the metals on the water 
increases the energy of the chemical,circle. Hence water con- 
taining acids in solution answers best. The energy of the circle 
is increased by every repetition of the pair of metals with the 
liquid between each, because every pair of metals adds its own 
energy to that of the other. Alkalies are attracted to the same 
metal as hydrogen, in consequence of their excess of combusti- 
bility ; while acids, for the contrary reason, are attracted to the 
same metal as the oxygen. It is obvious that all the other 
phenomena of the voltaic circle may be explained on the same 
principles. 
The reader who is acquainted with Mr. Donovan’s mode of 
explaining the action of the voltaic battery, will perceive a con- 
siderable resemblance between his hypothesis and that of Prof. 
(Ersted; though certainly there is a considerable difference 
between the two. Our author’s view of the subject is less 
encumbered with hypothesis than that of Mr. Donovan; and he 
does not suppose the transfer of the chemical attractions and 
repulsions which constitutes the foundation of Mr. Donovan’s 
hypothesis, and which is a supposition very difficult to conceive 
or to admit. 
Cuarp. 1V.—Of Electric Forces considered as Chemical Forces. 
Electricity exhibits two forces of such a nature that they 
destroy the activity of each other. These, therefore, are truly 
opposite forces. One of these has received the name of vitreous 
or positive electricity, while the other is called resinous or 
negative electricity. Each of these forces has a repulsive acti- 
vity for itself, and an attractive activity for the opposite force. 
Hence they are capable of retaining each other, so that it is no 
longer possible to perceive any external signs of their presence. 
A body may even contain an immense quantity which escapes 
