TIDAL EVOLUTION. 7 



solid crust is also to a certain degree attracted to the moon, 

 away from the waters on the distant side from the satellite, thus 

 leaving the waters in a high wave behind. This is the explana- 

 tion of the neap tides. The intervening positions between the 

 two high tides, that is, the positions which are as it were, in 

 quadrature with the moon, form the ebbs. 



Thus, with a little reflection, we find that the earth is 

 forced through the attraction of the moon to depart from the 

 spherical form and made as it were to bulge out into an oblate 

 ellipsoid, the major axis of which keeps forever following the 

 direction of the moon in her ceaseless journey around her 

 primary. 



But some of you may think that these tides certainly are of 

 a rhythmic character. Do they not rise and fall? Are they not 

 a very pulsation of the ocean, now strong, now weak, but 

 ever changing in a regular periodic succession ? And have I 

 not myself just given the rise and fall of the tides as an illus- 

 tration of rhythmic phenomena? 



In answer to this I will simply propose that we 

 change our point of view. No doubt, from a terres- 

 trial and therefore limited standpoint the tides do appear 

 to be of a rythmic character. But let us rise from the 

 terrestrial to the general, to the truly philosophical point 

 of view, rising high enough to view the whole globe at 

 a glance; or let us, perhaps, rather view the axial rotation of 

 our earth from the standpoint of the moon. What now has 

 become of the rise and fall of the tides and their rythmic char- 

 acteristics? Where now will we detect their periodic spring and 

 neap, their flood and ebb? All have disappeared, being only 

 relative phenomena, caused by our terrestrial surroundings and 

 confined limited point of view. In their place we behold only 

 one single gigantic tidal wave, extending from pole to pole 

 parallel to the earth's axis, forever following in the wake of 

 the moon's course. 



What a worthy subject it would be for us this evening to 

 consider some of the extraordinary physical phenomena con- 

 nected so closely with the action of the tides, such as their 

 surprising smallness in midocean, in the Mediterranean sea, 



