COAL AS A RESERVOIR OF POWER. 739 



we have discovered in our artificial flame. "VVe pursue this very in- 

 teresting discovery, and we find that several metals which give color 

 to flame, and produce certain lines, when subjected to spectrum analy- 

 sis, are to be detected in the rays of the sun. Therefore our inference 

 is, that some substances, similar to the terrestrial bodies, with which 

 we are familiar, are actually undergoing a change in the sun, analo- 

 gous to those changes which we call combustion ; and, more than this, 

 we argue that the high probability is, that all solar energies are de- 

 veloped under those conditions of chemical change that, in fact, the 

 sun is burning, and while solar matter is changing its form, Force is 

 rendered active, and as ray-power passes off into space as light, heat, 

 etc., to do its work upon distant worlds, and these forms of Force are 

 expended in doing the work of development on those worlds. This 

 idea theory hypothesis call it what we may involves of neces- 

 sity the waste of energy in the sun, and we must concede the possi- 

 bility of the blazing sun's gigantic mass becoming eventually a globe 

 of dead ashes, unless we can comprehend some method by which 

 energy can be again restored to the inert matter. Certain it is that 

 the sun has been shining thousands of years, and its influence on this 

 eai-th we know to have been the production of organized masses, ab- 

 sorbing the radiant energies, in volumes capable of measurement. On 

 this earth, for every equivalent of heat developed, a fixed equivalent 

 of matter has changed its form ; and so likewise is it with regard to 

 the other forces. On the sun, in like manner, every cubic mile of sun- 

 shine represents the change of form of an equivalent of solar matter, 

 and that equivalent of matter is no longer capable of supplying Force, 

 unless by some conditions, beyond our grasp at present, it takes up 

 again that which it has lost. That something of this kind must take 

 place is certain. The sun is not burning out. After the lapse of 

 thousands of years we have the most incontrovertible evidence that 

 the light of to-day is no less brilliant now than it was when man 

 walked amid the groves of Eden. We may venture farther back into 

 the arcana of time, and say that the sun of the past summer has shone 

 with splendor equal to the radiant power which, myriads of ages ere 

 yet man appeared on this planet, stimulated the growth of those luxu- 

 riant forests which perished to form those vast beds from which we 

 derive our coal. Not a ray the less is poured out in any hour of sun- 

 shine; not a grain-weight of matter is lost from the mass of the 

 sun. If either the sunshine were weakened, or the weight of the vast 

 globe diminished, the planets would vary in their physical condi- 

 tions, and their orbits would be changed. There is no evidence that 

 either the one or the other has resulted. Let us see if we can guess 

 at any process by which this stability of the solar system is main- 

 tained. 



It was first shown by Faraday, in a series of experimental investi- 

 gations which may be regarded as the most beautiful example of in- 



