DEDUCTIONS FROM THE TIDES. 33 



Hudson Bay, which is far more land-locked and is in a much higher latitude 

 and much farther from the assigned source of derivation. Singularly- 

 enough, the tides in Hudson Bay are several times as high as those of the 

 Mexican Gulf and the Caribbean Sea. 



If it be objected that the North Atlantic is too narrow and too peculiar 

 in its relations to give these singular features much weight, a similar Hne 

 of inspection may be apphed to the Pacific, whose breadth and equatorial 

 position make it preeminently favorable for a westward accumulation of 

 the tide. From the mass of data now made available by Harris's compila- 

 tions and harmonic reductions, it appears that the tides on the eastern 

 side of the Pacific as recorded on the American coasts are notably stronger 

 than the average tides on the Asiatic coasts. A comparison of the tidal 

 heights on the Pacific islands, though the data are inadequate, also fails to 

 show a concentration on the western side. 



On the old cotidal charts, and more definitely on the new ones of Harris 

 (fig. 3), it appears that the dominant tide of the Pacific originates in a 

 singular loop near the Galapagos Islands, off the coast of South America, 

 from which, on one side, a wave moves easterly and southeasterly to the 

 South American coast in strong force, then down it to the extremity of 

 the continent, where, according to Harris, it rounds Cape Horn and moves 

 up the eastern coast of Patagonia to about the mouth of the Rio de la 

 Plata. On the other side of the Galapagos loop, a wave moves north- 

 westerly along the North American coast, and then westerly toward the 

 Asiatic coast. In the heart of the Pacific, Harris locates three amphi- 

 dromic centers of practically no tide (fig. 3). While these are not directly 

 based on observations, they are believed by this industrious and original 

 student of the tides to be in accord with the data derivable from the observed 

 tides of the central Pacific Islands. This singular dispersion of the Pacific 

 tides from the vicinity of the Galapagos Islands near the eastern border 

 of the great ocean, as shown on the old charts, suggested to me, perhaps 

 a decade ago, that the water-tides might be largely derived from the litho- 

 sphere rather than directly from the attraction of the moon and sun on the 

 water itself. The rocking of the basins, first by a lift on the east side and 

 later by a lift on the west, under the progressive influence of the tide- 

 producing body, seemed to me more compatible with this behavior of the 

 tides than direct attraction on the water itself, which I supposed should be 

 less effective on the east side than on the west. The greater strength of 

 the tides on the east side of the Atlantic also strengthens the impression 

 that, whether this suggestion of derivation from the pulsations of the 

 lithosphere be of any value or not, the actual evolution of the tides involves 

 much more than the simple upward pull and westward drag of the waters 

 by the moon and sun. 



The recent theory advanced by Harris,^ that the tides are largely due 

 to the cumulative agency of stationary oscillations in such segments of 

 the oceans as may act commensurately with the tidal forces, goes far to 

 relieve the foregoing and similar features of the tides of their seeming 



» "Outlines of tidal theory," Rollin A. Harris, Rep. U. S. Coast and Geodetic Surv. 

 1900, app. 7, pp. 535-699. 



