36o 



SCIENCE 



[Vol. XIX. No. 490 



through these passages the Arctic currents flow and largely occupy 

 the low sea-level, caused by the westerly winds along the Ameri- 

 can coast from Greenland to Florida. We also see the tropical 

 waters lieaped against Mexico, attracted to the same low sea-level, 

 thus causing the Gulf Stream. But the waters of this stream, 

 while on their northern passage, are so obstructed by the opposing 

 Arctic currents, they fail to reach the higher northern latitudes; 

 consequently heavy glaciers have gathered and still are gathering 

 on Greenland and other Arctic shores, and this increase of cold 

 will continue in unison with the growing cold of the Antarctic 

 regions until the Arctic channels are closed with ice, and a north- 

 ern ice-age completed. But when the Arctic channels are closed, 

 the Gulf Stream will be able to reach a much higher latitude than 

 now, as it would meet with no obstruction except the return cur- 

 rent of its own waters, which would probably flow down the east 

 coast of Greenland, where the Arctic waters now flow. Thus, 

 with less obstruction, the movement of tropical waters into the 

 Arctic regions, which, in connection with increasing warmth in 

 the southern hemisphere, would be able to bring about a warm 

 period in the northern latitudes of considerable duration, on ac- 

 count of the glaciers filling the Arctic straits being situated to 

 the windward of the tropical currents, and, in consequence of 

 their cold location, would be the last ice to melt in the northern 

 regions. 



It has been the opinion of several writers that should the whole 

 of the warm Gulf Stream water flow into the Arctic Ocean it 

 would probably remove the ice of Greenland, and it is reasonable 

 to suppose that such would be the case. But, as far as I know, 

 such theorists always fail to explain how tropical waters are ever 

 made to flow into the high latitudes. They have nothing to say 

 of the low sea-level trough, caused by the westerly winds, extend- 

 ing from Georgia to Greenland, and thus attracting both the Arc- 

 tic and Gulf-stream waters in opposite directions over fifteen 

 hundred miles along the American Coast. For were it not for 

 this low sea-level the Gulf Stream would not be able to move so 

 far northward as it now flows, but would spread out. were the 

 Atlantic a level plain, and become a drift current much further 

 southward; especially with the Arctic currents opposing it from 

 the north. 



Professor Geikie asserts that there can be no doubt whatever 

 that periods succeeding the Tertiary have been characterized by 

 great oscillations of climate — extremely cold and very genial 

 conditions alternating; and that during the frigid period, where 

 we now have the greatest rainfall, the greatest snowfall took 

 place. He also says, that during such times changes in the 

 relative level of the land and sea had taken place. But he did 

 not believe that there had been any great movement in the earth's 

 crust. For while giving his views on the earth-movement 

 hypothesis he declared that there was not the least evidence of 

 great continental elevations in the northern hemisphere, and even 

 if such improbable earth-movements were admitted they would 

 not account for the glacial period. The assertions of Professor 

 Geikie, that where we now have the greatest rainfall, in glacial 

 times the greatest snowfall took place, shows that the prevailing 

 winds during the cold period must have blown in the same direc- 

 tion they now blow. Consequently, the great ocean currents, 

 being governed by the prevailing winds, were during the glacial 

 period moving in the same direction they now move. But the 

 great Southern Ocean drift current lost its independent movement 

 when the Cape Horn channel was closed with ice; which, accord- 

 ing to the common course of nature must again be brought 

 about. Thus, in the future, as in past glacial periods, the strong 

 westerly winds that sweep the Southern Ocean would blow the 

 surface waters away from the leeward side of the ice isthmus 

 and so cause a low ocean-level ; and it appears that the only water 

 that could be attracted to this low sea-level would be the tropical 

 water heaped against Brazil by the trade-winds. This tropical 

 water on gaining the low ocean-level would spread over its wide 

 depression, where the westerly winds would cause it to become a 

 drift current, and in this way it would be moved along the shores 

 of the Antarctic continent past the South Indian and South 

 Pacific oceans and eventually be forced against the Pacific side of 

 the ice isthmus and Patagonian coast, and so cause a high ocean- 



level. This high level would vastly increase the volume of the 

 Humboldt current, which would flow, as it now flows, down the 

 South American coast to the equatorial latitudes, where it would 

 become the main source of the great equatorial current. The 

 latter current with an increased volume would also move as it 

 moves to-day, across the Pacific, and through the East India pas- 

 sages into the Indian Ocean, where it would flow on partly as a 

 drift current until it joined the great Mozambique current, which 

 would flow southward along the east coast of Africa, the same as 

 it now flows. At this age, when this continuation of the great 

 equatorial stream gains the latitude of the Cape of Good Hope, its 

 waters are largely turned eastward by the great drift current of 

 the Southern Ocean; but a considerable portion of its waters turn 

 towards the west forming the Agulhas current, which flows 

 around the Cape of Good Hope into the Atlantic, where it min- 

 gles with the cooler currents, which branch off from the great 

 southern drift current; and so in connection with the latter 

 waters is moved by, the south-east trade- winds towards the equa- 

 torial Atlantic and coast of Brazil. Thus it will be seen that the 

 Agulhas current, while giving additional warmth to the Atlantic, 

 serves to retard somewhat the advance of the coming cold 

 period. 



The Agulhas current also partly serves to replenish the water 

 which at this date is forced from the South Atlantic by the strong 

 westerly winds into the southern Indian and Pacific oceans. For 

 it appears that more water is now removed by such winds from, 

 the South Atlantic than enters it from the Cape Horn channel. 

 This channel being less than half of the breadth of the westerly 

 wind-belt of the Southern Ocean, the drift currents do not all pass 

 through it from the Pacific into the Atlantic. Consequently, a 

 considerable portion of the drifting water turns northward west 

 of Cape Horn, and so forms the Humboldt current. Therefore, 

 the Agulhas stream, which even now assists in replenishing the 

 Atlantic, would be a much stronger current with the Cape Horn 

 channel closed ; because the South Atlantic waters would continue 

 as now to be forced eastward by the strong westerly winds, yet 

 they could not be replenished as they are to-day directly from 

 the Pacific; therefore, the waters of the whole Atlantic Ocean 

 would be correspondingly reduced. Such conditions alone would 

 greatly swell the warm Agulhas stream at the culmination of a 

 frigid period, and thus greatly assist the Atlantic in its operations 

 while bringing about a warm period. Dr. Croll, in his astro- 

 nomical theory, declares the ice periods of the northern and 

 southern hemispheres to be consecutive. But when we consider 

 the wide connection and circulation of the tropical seas it seems 

 impossible for a glacial epoch to be perfected in one of the hemi- 

 spheres with a mild climate extending over the opposite portion of 

 the globe. And it appears to me that the tropical lands I have 

 visited show indications of having at times experienced a tem- 

 perature sufficiently cold for snow and ice to have gathered on 

 their highlands, and in some locations glaciers may have extended 

 to the sea. Besides it is well known that Alpine plants exist on 

 the high mountains of the tropics; and it also appears that during 

 some ancient period the climate has been favorable for their 

 crossing the lower lands of the torrid zone, which lends to show 

 that the frigid periods of the two hemispheres were concurrent. 



C. A. M. Tabee. 



Wakefield, Mass,, June 13. 



European Origin of the White Race. 



I HAVE received so many letters questioning my statement in 

 Science, March 25, that Omalius d'Hallo.y, and not Dr. Latham, 

 was the first to maintain the European oi'igin of the while race, 

 that it seems due to the former scientist, as well as to myself, to 

 quote his words. Even such a thorough-paced archseologist as M. 

 Salomon Reinach, of the National Museum, St. Germain-en-Laye, 

 writes: " Where did you hear that Omalius had presented the 

 European theory before Latham? I am sure that it is not so." 



Now if these inquirers will turn to the Bulletins de I'Academie 

 Royale de Belgique, Tome XV. , No. 5, May, 1848, they will find 

 an article of 16 pages, entitled " Observations sur la Distribution 

 ancienne des Peuples de la Race blanche,"' par M. J. J. Omalius 



