THE GEOLOGIST. 



spot nearer, no matter how slightly nearer, to the sun, although upon 

 the same straight line, and so year by year the circumference of the 

 orbit would be ever constantly contracting; and what must be the 

 inevitable result ? — a spiral orbit ! 



Now, let us consider what would be the physical results of this 

 retardation producing a spiral orbit. If the retardation be ten feet 

 annually, — we will take it hypothetically as such for the present, and 

 to still further simplify the proposition we want to put, we will also 

 take for the present a perfectly circular orbit, because by so doing 

 we shall get a total result at once, instead of having to eliminate a 

 total result from a period of duration. If the earth be retarded ten 

 inches a month, the total retardation would be ten feet for the year, 

 so we may assume, for simplicity of explanation, a full total at once. 

 Now, then, if the earth were thrown back in her orbit suddenly for 

 ten feet, what effect would her momentum exert upon her constituent 

 material particles ? Would not every one of these particles have a 

 tendency to fly ou, and would not this tendency produce tension and 

 inter-particle motion, and thence, of course, friction, rearrangement, 

 crystallization, upheaval, and subsidence of masses, and internal heat? 

 Has the internal heat of our globe any other source than results 

 from the constant retardation of our earth in a spiral orbit ? And is 

 not the primary physical force which evolves all, or principally all, 

 structural alterations and constituent rearrangement of rock-masses ? 

 And if so, is not this force calculable ? If the earth be retarded ten 

 feet per annum, will not this force be equal to the momentum of the 

 mass of our globe for the time our globe takes to pass through ten 

 feet of space ? Given this rule, can we not estimate the quantity of 

 heat that would be evolved ? It seems to me we can ; and as by such 

 a cause the temperature of the lohole of the interior of the earth be- 

 neath that mere rind, subject to solar and atmospheric variations, 

 might be and would be equally warmed to a certain point, whatever 

 that may hereafter be determined to be, and thus the internal heat 

 would be naturally accounted for by natural phenomena. And even 

 if it should be found that this cause should be a sufficient source for 

 an intense degree of heat, — and it is possible it may be, — we should 

 be relieved of much of the embarrassment which the internal heat 

 theory provokes, because we never can get its theorists to assign a 

 natural and intelligible cause for its production and maintenance. 



