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forms, when the bodies are altered in either by external 
forces. Now, considering that such ultimate particles, 
called “ atoms ” and “ molecules ” are not discoverable by 
any analysis of, or known mutations of matter, to assert the 
exertion of such invisible moving forces, as apart from the 
tangible matter exerting those forces, is clearly a gratuitous 
assumption, unwarranted by any known properties of 
material bodies. With respect to the solar rays, we have 
many striking evidences of their chemical action in terres- 
trial phenomena; but no proof whatever has yet been 
adduced, to show their mechanical force or action upon 
tangible bodies, unless their impinging on the optic nerves, 
giving the sensation of light, may be held to be a mechanical 
action ; but even if this be so, the force exerted can be but 
slight. Wherefore these newly discovered forces must 
“ vanish into air, into thin air.” 
From the same high authority (before named) after 
giving a brilliant exposition of “the source of the solar 
rays,” or as it is termed, “the origin and sustentation of 
the heat of the solar furnace” — and showing how the 
growth of vegetables depends on the solar influence, and 
that our stores of coal come from plants, also that by the 
combustion of coal, steam-power is obtained and machinery 
driven, &c. &c. The author then adduces the following 
case, namely — 
“ From machine power, we turn to muscular power. 
Between the steam-engine and living bodies there is the 
closest analogy. The nutritive materials upon which life 
depends, are no more nor less than combustible substances^ 
which actually undergo a slow combustion. The conversion 
of food into work done, is effected by the same process as 
that which turns coal, or wood into motive force.” 
That we must eat to live, and the steam-engine must 
have steam to work it, are simple facts that require no 
comments; but the forces exerted to sustain the movements 
