1.58 /. Croll — Influence of the Gulf-stream. 



climate of Northern Europe and the Arctic regions ? " the answer can 

 be given in the most positive manner by determining the absolute 

 quantity of energy in the form of heat conveyed by the stream. 



The fact of the climate of our island being greatly modified by the 

 heat derived from the G-ulf-stream has lately been called in question 

 by Mr. A. G. Findlay and some others. 



Mr. Findlay takes the breadth of the stream, as it issues from the 

 Gulf of Mexico, at 45 miles, and its depth at 900 or 1200 feet, and 

 maintains that a stream of this size, leaving the Gulf with a velocity 

 of only a few miles an hour, would not be able to force itself across 

 the Atlantic and onwards to the Polar Eegions against the Arctic 

 current and other impediments in its way; and even supposing it 

 were able to do this, still its volume, he asserts, is too small and its 

 temperatiare too low to produce the thermal effects attributed to it. 

 It is certainly, no doubt, true that if the Arctic current was an 

 opjjosing cun-ent as well as a contrary one, and if the Gulf-stream 

 had to push its way to the Polar Eegions by means of some impulse 

 received before leaving the Gulf, it is not at all likely that it would 

 ever reach to even the latitude of New York, far less to the 

 shores of Great Britain. But neither the Gulf-stream nor any 

 other ocean current moves in this manner. It is, however, not with 

 this phase of the objection that I am at present concerned, but with 

 the other and more important one, viz. that a current 45 miles broad 

 and 900 or 1200 feet deep is too small to convey the amount of heat 

 necessary to produce the warming effects usually attributed to the 

 Gulf-stream. 



Tliere are perhaps few, if any, who have not actually subjected the 

 matter to calculation, but would be inclined to agree with Mr. Find- 

 lay, that a stream so comparatively small, leaving the Gulf of Mexico 

 at a temperature of not over 70° or 80'^, and losing heat during a 

 journey of several months across the Atlantic, could not possibly be 

 able to maintain the winter temperature of the whole of Northern 

 Europe 20*-' or more above the normal. They would naturally con- 

 clude that the only way of meeting Mr. Findlay's objection would 

 be by denying that the stream is so small as he asserts it to be. 



Although [ am inclined to believe that Mr. Findlay has under- 

 estimated the volume of the Gulf-stream, still I can see no necessity for 

 insisting on this in order to be able completely to meet his objection ; 

 for, taking his estimate of its size, it can be proved that his conclu- 

 sion is incorrect, as the following, it is hoped, will show. 



In the following calculations the breadth of the stream is taken 

 at 50 miles, and its depth at 1000 feet, and its velocity at four miles 

 an hour. This is almost exactly Mr. Findlay's estimate. The tem- 

 perature of the water on leaving the Gulf is taken as low as 65°. 



" The enormous effect that ocean-cuiTents have in equalising the 

 temperature of our globe by diminishing the difference between 

 the temperature of the equator and the poles, has never been duly 

 estimated. This will be seen if we merely consider for a moment 

 the effect produced by one curi;ent alone, viz., the Gulf-stream. The 

 total quantity of water conveyed by this stream is probably equal to 



