THE TIDES 181 



water to leave the axis, and press towards the circumference ; it is 

 therefore, urged against the pail, and forced up its sides, till the 

 excess of height, and consequent increase of pressure downwards, 

 just counterbalance its centrifugal force, and a state of equili- 

 brium is attained. The experiment is a very easy and instructive 

 one, and is admirably calculated to show how the form of equili- 

 brium accommodates itself to varying circumstances. If, for ex- 

 ample, we allow the rotation to cease by degrees, as it becomes 

 slower we shall see the concavity of the water regularly diminish ; 

 the elevated outward portion will descend, and the depressed 

 centre rise, while all the time a perfectly smooth surface is main- 

 tained, till the rotation is exhausted, when the water resumes its 

 horizontal state. (The italics are all his.) 



Inasmuch, however, as I previously contended that 

 Newton erred in not construing only a half of the equa- 

 torial protuberance as being centrifugalized, and in not 

 allowing for the fact that the oceans are only a little more 

 than two miles deep, let us generously accept even these 

 low figures. According to the best authorities, the weight 

 of the actual oceans is, in round numbers, 1,400 quad- 

 rillions of tons, of which, let us agree, only one-half is 

 energially upheld by drafts upon the earth's axial mo- 

 mentum. Then it would appear, recourse being had to 

 our rule, that the planet is using up only 700 quadrillions 

 of horse-power, perennially, instead of the six quintillions 

 that we found before. (Compare, also, Young, G. A., Art. 

 154.) 



Again, accepting Sir Robert Ball as spokesman for 

 his fellow astronomers to the effect that the energy that 

 produces the tides emanates not from the sun or moon, 

 but out of the earth's store of centrifugal momentum, let 

 us see what this, also, amounts to. Flammarion gives the 

 sum of the lunar and solar tides as (approximately) 30 

 inches at the equator. Taking their average height for 

 the whole world as 15 inches, and limiting this again to 

 only half the ocean surface (75,000,000 miles), gives a 

 weight of water thus alleged to be perpetually whirled 

 upward by the earth of, in round numbers, 80 trillions of 

 tons. As this action is going on all the time, it means 

 that, on this second count, the centrifugal force is wasting 

 away at the steady gait of 80 trillions of horse-power. 



