372 
Mr. Donovan read the first part of a paper *¢ on the sup- 
posed identity of the agent in the phenomena of ordinary elec- 
tricity, voltaic electricity, electro-magnetism, magneto-elec- 
tricity, and thermo-electricity.”. This part was introductory 
to the subject of the remaining portions, which will be de- 
voted to an attempt to prove that the hypothesis at present 
accredited by philosophers, as adequate to explain the pheno- 
mena of the electric fluid, under its various aspects, does not 
accord with well-observed facts. 
Its object was to render it probable that what is called 
the electric fluid, is not a simple element, as it is generally 
believed to be, but that it consists of several constituent ele- 
ments, each exercising a separate function; and many facts 
were referred to in support of the opinion. Reasons were 
assigned for believing that this hypothesis is more consonant 
with the general analogy of nature, than the supposition that 
electricity is a homogeneous fluid. References were also given 
to the opinions of those who coincide in this view. 
After a full consideration of the facts and arguments, Mr. 
Donovan summed up as his conclusion, that the electric fluid, 
in the comprehensive sense of the word, including frictional, 
voltaic, electro-magnetic, magneto-electric, and thermo-elec- 
tric, does not consist of one homogeneous element, but of 
several, viz., heat, light, magnetism, electricity proper, che- 
mical attraction, the physiological agent, and the deflecting 
agent: that the difference between the various exhibitions of 
it just mentioned depends on the proportions or energy of the 
constituent elements, or the influence of the modifications 
which, under different circumstances, they are capable of ex- 
erting on each other. This influence is probably of the same 
character as that which the forces of nature exercise on each 
other, on the great scale of creation, controlling, antagonizing, 
and modifying each other’s effects, thus producing the diver- 
sified phenomena of the universe, but rarely acting indepen- 
dently. 
