32 THE TIDAL PROBLEM. 



meet one another within the inter-island water-bodies. There seems to 

 be no definite perpetuation of the Pacific tides into the Indian Ocean, 

 these bodies, though connected both north and south of Australia, acting 

 in essential independence. While the long-prevalent view that the tides 

 of the Atlantic and Arctic Oceans are derivatives from the Southern Ocean 

 still has the apparent support of observational data, there are many facts 

 that seem to indicate that this is only a part of the truth. A derivative 

 wave should gradually die down as it progresses; but, notwithstanding 

 the distance of the North Atlantic from the Southern Ocean, the tides are 

 higher there than those of the South Atlantic. A derivative wave should 

 be intensified in passing a constriction and should be lowered in an expanded 

 water-body beyond; but, notwithstanding the reduction of the Atlantic 

 breadth between Brazil and Sierra Leone, the tides are particularly high 

 in the lee of the great nose of Africa north of this constriction. The north- 

 easterly-trending coast of New England and the Provinces stands directly 

 athwart an unobstructed stretch of sea reaching back to the Southern 

 Ocean along the line of assumed propagation, and yet the average tide on 

 this coast is notably less than that on the European coast of the same lati- 

 tudes, though this hes behind the African projection. Comparing the tides 

 on the Atlantic islands— whose isolation should render them measurably 

 free from local influences, save those of their own basal slopes and their 

 harbors— it is notable that the tides on the islands of the South Atlantic 

 average less than half as much as those of the islands of the North Atlantic. 

 The tides on the islands in the far North Atlantic, and even some of those 

 in the borders of the Arctic Ocean, are singularly high, such as those of the 

 Faroes, Shetlands, Orkneys, Hebrides, Iceland, Greenland, Jan Mayen, and 

 some Arctic Islands of North America. On the purely derivative theory, 

 these tides must be supposed to have been travehng 24 hours or more 

 since they left the place of their origin, and those in the high north have 

 been subject to the damping effects of polar ice. 



There are not a few anomahes that are very puzzling on the supposition 

 of a westward drag of the waters by the moon and sun. The northeast 

 coast of South America trends northwesterly and the Central American 

 states continue the trend in fair alignment. Over against this, the North 

 American coast has a southwesterly trend, meeting the projection of the 

 northwesterly trend of South America on the coast of Guatemala, thus 

 forming a wide eastward-facing angle. From this point to Cape Race, 

 the angular distance is 40° and from it to Cape St. Roque, 50°, while the 

 open eastward-facing mouth between Cape Race and Cape St. Roque is 

 about 50°. On the hypothesis of a westward-moving tide, cumulative 

 toward the west, we should expect high tides in the Antilles, the Caribbean 

 Sea, and the Gulf of Mexico. If it is thought that the last two bodies are 

 protected from this high tide by the Antilles, the tides on the eastern side 

 of the Antilles should be markedly high. The record does not show this. 

 The tides on the African and European coasts opposite are notably higher 

 than those which might be supposed to be unusually concentrated within 

 this angle. As bearing on any supposed protection of the Gulf of Mexico 

 and the Caribbean Sea by the Antilles, a comparison may be made with 



