1885 .] 
The Heat of the Sun t 
135 
The Regenerative Theory 6 
.^■his theory , which I have so named because of its most 
characteristic feature, is at present literally and absolutely 
in its infancy, It first saw the light in March, 1882, having 
been proposed in a paper entitled the “ Conservation of 
Solar Energy, read before the Royal Society of London 
by the kte Sir C. W. Siemens, F.R.S., the President of the 
bntish Association for 1882-83. It essentially differs from 
all the other theories in that it supposes the acftion of the 
Sun, in sending out light and heat, to be “ capable of pro- 
longing solar energy to the remotest future.”* But if it is 
, st f? r suc , h A time > ^ is a physical necessity that very 
little of anything should be used up or expended. Accord- 
mgly the aCtion is maintained by the energy being conserved 
and protected from loss. This is accomplished by supposing 
reciprocal actions to go on using only the same materials, 
but under different conditions. The different conditions are 
those which obtain in or near the Sun, and those of inter- 
planetary space. In the one case we have intense heat, and 
in the other equally intense cold ; and I may here remark 
that it would be impossible to conceive of matter being 
placed in positions which afford conditions possessing 
greater contrast. Matter is supposed to be subjected, at 
different times, to these different conditions, and its behaviour 
under such conditions produces in the one case the heat and 
light of the sun, and in the other the materials necessary 
foi maintaining this heat and light. Without further preface 
we will state Dr. Siemens’s theory in as nearly as possible 
his own words. 
After briefly stating the various theories, and offering- 
certain objections to them, he says— “ The true solution of 
the problem will be furnished by a theory, according to 
which the radiant energy which is now supposed to be dissi- 
pated into space, and irrecoverably lost to our solar system, 
could be arrested and brought back in another form to the 
Sun itself, there to continue the work of solar radiation.” 
After this preliminary assertion he proceeds to state the 
fundamental assumption that all space is filled with highly 
rarefied gaseous bodies, including hydrogen, oxygen, nitrogen, 
These are the concluding words of the first paper on the subjed which 
was communicated to the Royal Society. In a letter to the present writer 
However, Dr. Siemens states that he does not mean by this that his theory 
provides anything in the way of perpetual motion, but only that he considers 
u capable of continuing solar radiation to a very remote future.” 
