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experiment has taught us that the various effects ascribed to 
the supposed forces of matter are mutually interchaugeable ; 
that force^ arrested in one manifestation and seemingly ab- 
sorbed, is not destroyed, but transmuted. The old fable of 
Proteus, as has been often said, is exactly realised in nature 
as she appears to the eye of modern science. Bind her you 
cannot, for she forthwith reappears in a new shape. The 
motion of the smithes hammer, arrested by the anvil, sets the 
atoms vibrating and is changed to heat ; whilst heat in the 
furnace of the steam-engine results in molar motion. An 
electric current can be made to produce magnetism, and vice 
versa magnetism to give rise to the phenomena of electricity. 
The galvanic current is an effect (in the physical sense) of 
chemical changes, and is also (in the same sense) a cause of 
them. Heat, electricity, radiant energy, and chemical action, 
are mutually convertible, can all produce motion, and be, in 
turn, produced by it. More than this, there is reason to con- 
jecture that the effects of force, differing as they do in their 
action on ourselves as sentient subjects, may be identical when 
considered in their own nature, or, as we say, objectively ; 
and that all are resolvable into modes of motion. Such an 
objective identity with motion is considered to be already 
established in regard to light and heat. Motion appears the 
simplest effect of force, and everything points to the probable 
resolution of all other phases or effects of force into this one 
mode of manifestation. That accomplished, physical science 
will have verified the datum of Democritus. We shall have 
matter in motion, in void space, as the apparent beginning of 
physical things. There the science of nature must come to a 
stand ; the investigation of phenomena can take us no further 
back. But behind the ultimate phenomenon of motion the 
materialist assumes a force as causing motion, and through 
motion, in its successive phases, producing all other pheno- 
mena. This force is supposed to reside in atoms, the ulti- 
mate particles of matter. In modes yet to be explained it 
leads on to combinations of ever-increasing complexity, and 
is displayed in higher and higher developments of power; 
rising from mechanical to chemical, from chemical to vital, 
from vital to mental manifestations. Without diminution or 
increase, by imperceptible gradations, it ascends through the 
infinite series of physical existence, — from the glowing 
hydrogen and nitrogen of the incandescent nebula to the 
light of reason in the brain of man. Such is the theory wo 
have to deal with. 
It will be seen that the Materialist herein agi*ees with the 
Theist, — that he asserts, and, so to speak, believes in, a First 
