On Heat and Light. 
[November, 
684 
transmutation of bodies, and heat and light are the most 
important elements in connection with all the phenomena 
of vital aCtion. By their means, out of the same soil and 
air is evolved the tender bud, the green leaf, the woody fibre, 
every form and description of vegetation, every variety and 
tint of colour, every kind of odour, and numerous other 
qualities by which our several senses are either obnoxiously 
or agreeably influenced. 
And yet it is said that light and heat can create nothing or 
destroy nothing; that they are mere modes of motion — the 
aCtion of the “ eternal and imperishable ” parts of the huge 
machinery of the universe, which change only in their 
relation to each other and not in their constitution. If this 
meant that heat and light can, in the absolute sense, create 
or destroy nothing, no objection could reasonably be made. 
We know nothing of either matter or motion beyond the 
impressions which they communicate to our consciousness 
through the senses. The forces of nature may indeed be 
described as only the agents by which the Supreme Creator 
works out His purposes in the universe ; but are we not, 
therefore, all the less justifiable, when we see these wonder- 
ful creations of light and heat, in denying that they are, 
what they appear to be, transmutations, in some degree, of 
the several materials or objects out of which they have been 
constituted ? That is, a transmutation (not of abstract 
matter, which is only a metaphysical conception) of the 
several qualities by which the objects are presented to our 
consciousness, and by which alone they are known to us ? 
Whilst some scientists treat heat as only a mode of 
motion, an accident or condition of matter, — others con- 
stantly refer to it as an entity of absolute power. Hence 
we read of calulations to determine how much of the sun’s 
heat is utilised in warming the planetary bodies, and how 
immensely more is wasted in space. I do not dispute that 
the sun, like everything else in Nature, is undergoing 
changes, or “growing older” ; but let this be remembered, 
that heat, such as it is known to us on the earth, may be 
something very different at its source ; that, in faCt, there is 
no reason to believe that the sun is being burnt up like the 
coals upon our fires. On the contrary, there is much reason 
to believe the reverse. Only a few miles up in the air it is 
freezing cold ; the light rays illuminate the regions above 
the clouds, but the heat rays are absent! Certainly no 
evidence this of immutable heat (or even of heat such as it 
is known to us by combustion) radiating from the sun into 
space. If we place a sheet of glass before the fire, the heat 
