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Ch. XXXIL] SUPPOSED SECULAR LOSS OF HEAT IN SUN. 213 



by the linearly arranged cones of the Andes or mountain 

 chains like the Alps. 



Supposed secular loss of heat in the solar system. — It is a 

 favourite dogma of some physicists, that not only the earth 

 but the sun itself is continually losing a portion of its heat, 

 and that as there is no known source by which it can be 

 restored, we can foresee the time when all life will cease to 

 exist upon this planet, and on the other hand we can look 

 back to the period when the heat was so intense as to be in- 

 compatible with the existence of any organic beings such as 

 are known to us in the living or fossil world. 



When we consider the discoveries recently made of the 



convertibility of one kind of force into another, and how 



light, heat, magnetism, electricity and chemical affinity are 



intimately connected, we may well hesitate before we 

 accept this theory of the constant diminution from age to 



age of a great source of dynamical and vital power. I shall 

 consider in the next chapter the connection of solar and 

 terrestrial magnetism, and the extent to which electricity 

 may be conceived to be a source of volcanic heat. ' 

 logist, in search of some renovating power, by which the 

 amount of heat may be made to continue unimpaired for 

 millions of years, past and future, in the solid parts of the 

 earth, although perpetually shifting the chief points of its 

 development, has been compared by an eminent physicist 

 to one who dreams he can discover a source of perpetual 

 motion, and invent a clock with a self-winding apparatus. 

 But why should we despair of detecting proofs of such a 

 regenerating and self-sustaining power in the works of a 



A geo- 



Divine Artificer? 



What is the origin of the force which 



governs the motions of the heavenly bodies ? It has been 

 likened to the intellectual power of the human will, which 

 mitiates and directs all our muscular actions. To define its 

 nature, has hitherto baffled the eflPorts of the metaphysician 

 and natural philosopher, but assuredly we are not yet so far 

 advanced in our knowledge of the system of the universe as 

 to entitle us to declare that a great dynamical force like that 

 of heat is on the wane. 



>4' 



