402 OBSEEVATIONS ON THE CUREENTS. 



extent of it, off the Banks of Newfoundland, and been in port a very con- 

 siderable time before them, by keeping out of the Stream ; whereas they 

 lengthened their passage by keeping in it. 



" The general course of the Gulf Stream being marked on the chart, I 

 would advise those who make the Northern passage from Europe never to 

 come nearer the inner line of it, by choice, than 30 to 45 miles ; and then 

 the probability will be that their passage will be assisted by the help of a 

 counter-current, which runs within it. In coming off a voyage from the 

 Southward, be sure to steer N.W. when approaching the Stream, if the 

 wind will permit you, and continue that course until you are within it, 

 which may be easily known by the temperature of the water, as before 

 mentioned. I have always considered it of the utmost consequence, when 

 bound in, to cross the Stream as speedily as possible, lest I should be 

 visited by calms or adverse winds, and driven far out of my way, which 

 would prolong the voyage considerably, especially in the winter." 



(391.) From the fact that when crossing the Gulf Stream from East to 

 West, the temperature suddenly fell when its Western edge was passed, 

 that is, coincidently with obtaining soundings, it was argued by Colonel 

 Williams, and long maintained, that the thermometer would certainly 

 indicate the approach to soundings by a fall in the temperature of the 

 water, in any part of the ocean. 



From the facts quoted, he infers that, " By the coincidence of these three 

 journals, at so great a distance of time, and without any connection with 

 each other, this important fact seems to be established : — A navigator may 

 discover his approach toward objects of danger, when he is at such a distance 

 as to be able easily to avoid them, by attentively examining the temperature 

 of the sea; the water over banks and shoals, in these regions, being colder, 

 in general, than that of the deep ocean." 



Now although this remark holds good as to this portion of the American 

 coast, and in some other parts of the world, under similar influences, yet 

 it is founded on a fallacy, and certainly has not that universal application 

 which former observers endeavoured to claim for it. This question is now 

 generally well understood, and it is only necessary thus to refer to it, as a 

 memorial of past times. When it was first promulgated, the extension of 

 the Arctic Current to the Southward in such a remarkable manner inside 

 the G-ulf Stream was not suspected. And although Mr. Redfield's views, 

 given hereafter, are now fully maintained, yet the more extended observa- 

 tions of the United States Coast Survey have revealed such singular facts, 

 that even now we must confess our knowledge of the compensating 

 system of the Ocean to be exceedingly imperfect. 



His investigations in the Blake led Lieutenant Pillsbury to remark: — "I 

 wish to particularly accentuate the fallacy of the idea, that the thermo- 

 meter may be relied upon to indicate the presence of a current. I can 

 see no way of utilizing it for the purposes of accurate navigation, nor 

 indeed of using it to indicate with certainty that the current is favourable, 

 or the reverse. The inner edge of the Stream is not necessarily marked 

 by a change of temperature. An abrupt difference may be encountered at 

 the true edge of the current, but the cold water may be moving N.E., or 

 the warm water flowing S.W." 



