146 PROP. E. HULL, LL.D., F.R.S., F.G.S., ON 



Jt is known that the Gulf Stream receives a large accession 

 of heat between the time that it enters the Caribbean Sea 

 and leaves the Gulf of Mexico through the Straits of Florida. 

 Off Cape S. Roque the sui-face temperature is 73° Fahr., and 

 on issuing from the Gulf it has risen to Sij° Fahr. having in its 

 passage gained 13 degrees of heat. Increasing its latitude by 

 ten degrees it loses but two degrees of heat, and with this 

 temperatiu'e of 84° Fahr. it crosses the 40th parallel, and 

 spreads itself out over thousands of square leagues — caiTying 

 its Avarmth into the Arctic regions, and giving an increase of 

 twelve degrees of temperature to the climate of the British 

 Isles above that due to latitude.* 



Geographers have exhausted the powers of illustration in 

 endeavouring to estimate the calorific effects of this great 

 oceanic river. Croll states that each cubit foot of water carries 

 from the tropics for distribution upwards of 1,158,000 foot 

 pounds of heat.t The estimates of Maury and Herschell are 

 still larger. According to the calculations of Meech the 

 amount of heat transferred to the Arctic regions by the Gulf 

 Stream is nearly half as much as that derived from the sun.:{: 

 Lastly, Professor J. D. Forbes calculated that the quantity of 

 heat thrown off in the Atlantic area by the Gulf Stream on 

 a winter's day, "would raise the temperature of the atmo- 

 sphere which rests upon France and the British Isles from 

 freezing point to summer heat.§ These statements will 

 suffice to represent the effects of the Gulf Stream as it exists 

 at the present day ; we have now to inquire to what extent 

 they would be modified under the view of the uprising of a 

 barrier of land connecting North and South America along 

 the line of the Antilles. 



We have already seen that the Gulf Stream gains thirteen 

 degrees of heat between C. San Roque and the Florida 

 Straits. If we allow one degree for the increase between 

 C. San Roque and the entrance to the Caribbean Sea, the 

 gain between this point and the Narrows will be twelve 

 degrees. If instead of entering the Caribbean Sea, the 

 stream passed northwards along the coast of continental 

 land, it would have been deprived of twelve degrees of heat, 

 but it would have gained some heat while flowing for 



* Croll calculates that on leaving the Gulf the mean temperature of 

 the Stream is not under 65° Fahr. ; Climate and Time, p. 25. 

 + Ibid., p. 25. 



\ Meech, Smithsonian Contributions to Knoioledge, vol. ix. 

 ^ Forbes, Travels in Norway, p. 202. 



