76 W. Hopkins on Changes of Climate. 
must manifestly be beyond the influence of the Gulf-stream, and 
our hypothetical line must consequently coincide with it. etd 
It would appear from the existing isothermals, that the Gulf 
stream produces little effect on the temperature, even in winter, 
on the eastern coast of America, as compared with its effect/on 
the western coast of Europe. There are several causes which 
may be assigned for this difference. After the stream has 
the straits of Bahama, it passes into an ocean of which the tem- 
perature is not much inferior to its own, and more norther:y its 
influence must be in some degree counteracted by the cold cut. 
rent proceeding southward throngh Davis’s Straits. Too the in- 
fluence of these causes may be ‘added that of the west winds 
which appear to prevail on the eastern coast of America as well 
as on the western coast of Europe. These, coming from the 
land in the former case, and from the ocean in the latter, tend to 
lower the winter nits eg on the American, while they raise 
it on the European coast. 
The deflection of the actual January isothermal of 32° to the 
northward on the westetn coast of N. America is considerably 
more rapid than that of my hypothetical line on the western 
coast of Europe. It also exceeds that of the lines of 41° and 
50° more than any mere law of continuity would seem to re 
quire. A considerable portion of the deflection is attributable, I 
doubt not, to loeal causes. In fact, a considerable current is 
scribed as setting northward along that coast from about the 45th 
degree of latitude, which may probably account for this extra 
deviation. The rernuinidees must be attributed to the influence of 
the Pacific Ocean, and would probably aecord with the sim 
deflection which I have given to my hypothetical line as arising 
from a similar cause on the western coast of Euro 
Supposing the isothermal we have been cousidering to be cor 
rectly drawn for our hypothetical case, there ean be no doubt, I 
conceive, of the approximate accuracy of the neighboring Jant 
ary isothermals as I have drawn them. In southern Asia t 
are compressed near to each other by the region of maximom 
cold which lies in the northeastern portion of Asia. As they ap 
proach the coast of western Europe they will necessarily bees 
more dilated, as I have represented them. 
12. Let us now examine the probable position of the isothet- 
mals for July in the hypothetical case of the non-existence of 
the Gulf-stream. These lines, it will be observed, as they now 
exist, have an alone a inflection to the north in northeast 
ern Asia. As we proceed westward from that region, they take 
a direction considerably south of west, until they eome under 
the influence of the anomalous temperatures of westert’ Europe 
This influence, however, does not sensibly extend so far south- 
ward in summer as in urs on account of the higher temper 
ture of the northern Atlantic in summer. The July isother 
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