722 TRANSACTIONS OP THE AMERICAN INSTITUTE. 



result will be that the moon finally will unite with the earth, that 

 is, fall clown ; but before that time another result will be brought 

 about, namely, the attraction of the moon in originating the tide 

 waves in the ocean, which running west, strike against the east 

 coasts of all lands, necessarily cause a retardation in the revolution 

 of the earth around its axis, which obstructed motion of the ocean 

 tide waves is after the law of the conservation of forces, converted 

 into a rise of temperature, which compensates a part of the earth's 

 loss of heat by radiation, and retards the cooling process ; how- 

 ever, we live now in a period of the earth's history that this 

 retardation is balanced by the acceleration due to the contraction 

 of the earth by cooling, which is still slowly going on, and explains 

 the rise and descent of certain parts of the continents, which always 

 is taking place, as observations prove. There was a time that the 

 cooling and consequent contractions was much greater than it is 

 now, and during that period the earth's rotary motion was accele- 

 rating ; and there will be a time that this cooling and contraction 

 will be less than it is now, and then the tide wave, caused by the 

 moon's attraction, will retard the rotation more and more, the 

 moon coming all the time nearer, its influence will increase and 

 the tide wave run higher, the earth turn slower and slower, till 

 finallyit will turn always the same side to the moon, then our 

 night and days will be as long as the time between two full moons. 

 The moon has, perhaps, gone through this very same process by 

 the attraction of the earth, at the time that part of her was still 

 liquid ; she is now entirely solidfied. 



Finally, in the course of ages, the moon must unite with the 

 earth, and the earth's solid crust will not only be broken up, by 

 the shock, its centre of gravity shifted, and every thing on its sur- 

 face utterly destroyed, but by the destruction of the moon's motion 

 an equivalent quantity of heat, several thousand degrees, will be 

 generated, enough not only to melt both, but to convert the whole 

 surface in a fiery ocean ; this molten glol)e will then go through 

 the same cooling process the earth has passed through, perhaps, 

 more than once ; another crust will be formed, geological deposits 

 will succeed one another, and a new vegetable and animal life will 

 appear, and pass again through the thousands of millions of similar 

 transformations, the relation between which constitute no-w, the 

 great problem of our age, of the origin and transmutation of 

 species. 



Mayer, indeed, thinks that it is highly probable that such pro- 



