24 KANSAS CITY REVIEW OF SCIENCE. 



times heavier than air, it is scarcely presumed that the trade winds develop 

 strength enough for such a task. 



Captain Maury next took into account the action of the sun's heat. He 

 beheved that the water at the equator was made lighter by the action of the sun 

 and flowed over the surface toward the poles. The cold water of the Polar seas 

 rushed in to take its place, but being heavier, formed a submarine current. 



Sir John Herschel maintained that such effects were impossible, since if the 

 waters became lighter, they could only have an upward, downward or sidewise 

 tendency. The latter could only result from the gradual sloping caused by the 

 bulf^ing of equatorial waters. Such a slope was too slight for such an effect. 



Richard A. Proctor, the astronomer, next takes the stand and argues for a 

 theory most generally held to-day. He proceeds to show that the great heat of 

 the sun at the equator has a drying as well as a warming effect on the waters. It 

 evaporates enormous quantities. This causes an intense suction to take place over 

 the whole equatorial Atlantic, and a submarine current of cold waters from the 

 Poles results and takes the place of the waters evaporated, also causing a surface 

 flow of warm waters toward the Poles. He says: "Having once detected the 

 main-spring of the Gulf Stream mechanism, or rather the whole system of oceanic 

 circulation — for the movements detected in the Atlantic have their exact counter- 

 part in the Pacific — we have no difficulty in accounting for all the motions which 

 that mechanism exhibits. We need no longer look upon the Gulf Stream as the 

 rebound of the equatorial current from the shores of North America. Knowing 

 there is an underflow toward the equator, we see there must be a surface flow 

 toward the poles. This must inevitably result in an easterly motion, as the 

 underflow toward the equator results in a westerly motion. We have, indeed, 

 the phenomena of trade and counter-trades exhibited in water currents instead of 

 air currents." 



I protest in the name of every student who attended the district school 

 twenty years ago, that this Proctorian theory is almost the exact wording of that 

 of Francis McNally in his " System of Geography," then studied. Yet at that 

 time, the Royal Geographical Society was questioning the very existence of the 

 Gulf Stream. In brief, our unpretentious geographer, who made but a three-page 

 analysis of the physical features of the earth, quietly advanced the only correct 

 theory of oceanic currents which were only advanced in after years by the great 

 scientists abroad as a result of a regular process of evolution of ideas, given in 

 the last paragraphs. To my own mind, all the causes taken into consideration, 

 which were either accepted or rejected, contribute their quota to oceanic currents. 

 The vast volume of water constantly contributed by the Mississippi and tributa- 

 ries, must render a portion of the prodigious force and volume of the Gulf 

 Stream possible. The trade winds banking up waters in the Gulf, must add 

 something by the reflux. The bulging of equatorial waters may contribute a 

 little. Of course, the evaporation by the sun is more potent than all other f irres 

 combined, but Richard A. Proctor hrs not an iota of claim to priority for that 

 theory. 



