THE TIDES 175 



rotating bodies. However, this new notion may be 

 rendered compatible by employing another method than 

 that of Newton to compute the tidal heights, a method, 

 too, that on the face of it is decidedly more logical in 

 every way, for it not only permits of the postulation of a 

 statical tide, but also shifts the task of producing the tides 

 in general from the centrifugal force of the earth to the 

 moon's attraction, where Newton initially meant to place 

 the credit. 



According to Sir John Murray, the average depth of 

 the oceans is 12,480 feet, or about 149,760 inches. Let us, 

 if you please, consider this water as a prize being 

 wrestled for by the earth, on the one hand, seeking to 

 maintain it in a quiescent state of equilibrium, and the 

 moon, on the other, striving to capture it from her. As 

 we have already seen, Newton estimated the moon's tidal 

 force as only 1-2,871,400 of gravity. To get a concrete 

 basis of comparison between these two forces, then, in 

 terms of ocean depth, all we need do is to divide 149,760 

 inches by 2,871,470 ; giving for a result approximately 

 one-twentieth of an inch, or about the thickness of shoe 

 leather. Of course, this result is ridiculously out of pro- 

 portion to the phenomena to be explained, but let the 

 blame fall on the theory, where it belongs, and not on my 

 method of computing it, which is logically sound. The 

 average daily rainfall for the whole earth is almost 

 exactly one-tenth of an inch. Assuming the average daily 

 evaporation from the surface of the sea to be the same, 

 there looms out the astounding reductio ad absurdum 

 that, on Newton's own showing, the sun's evaporating 

 effect is just twice as great as the moon's tidal force! 

 Besides, the sun raises Ms burden clear to the clouds. 



Most of my readers, I dare say, imagine, with Sir 

 Eobert Ball, the earth to be a body so enormous, and the 

 energy of its axial rotation so immeasurably great, that 

 the theoretical drains scientists impose upon it are 

 relatively too trivial to cut any material figure. Suppose 

 we investigate this matter in the spirit of the Missourian 

 and let us first take up the factor of the dynamical sus- 

 tentation of the equatorial ring. 



