444 Searles 7. Wood, Jun. — The Climate Controversy. 



current from lower latitudes, like the Gulf-stream, so that they 

 have been met with in vast chains extending beyond the visible 

 horizon. Thus they help to refrigerate the climate of latitudes 

 lying between the polar circles and the limit of their drift, which 

 extends almost as far as the latitude of the Cape of Good Hope ; 

 and it is to this cause that the advocates of the Geographical theory 

 of climate mainly attribute the lower temperature of the higher 

 latitudes of the southern hemisphere, as compared with similar 

 latitudes of the northern. The present colder condition of the 

 Antarctic region and of high southern latitudes is thus appealed 

 to by the advocates of both theory No. 3 and theory No. 4 ; by the 

 former on the ground that the aphelion point now occurs during 

 the southern winter, and on the ground, also, that this region fur- 

 nishes evidences of the cumulative tendency of ice and snow ; and 

 by the latter on the ground that it offers the most striking evidence 

 of the influence of geographical causes on climate. 



Sir Charles Lyell, in concluding his argument in the " Principles," 

 in support of the sufficiency of geographical causes, observed, " that 

 if at any former period the climate of the globe was much warmer 

 or colder than it is now, it would have a tendency to retain that 

 higher or lower temperature for a succession of geological epochs." 

 This, he considered, " would arise from the great depth of the sea 

 as compared to the height of the land, and the consequent lapse of 

 time required to alter the position of continents and great oceanic 

 basins." It is diflicult to reconcile this view with the intercalation 

 of glacial beds in the Permian formation of Britain and in the 

 Eocene and Miocene of Switzerland and Italy, to which he seemed 

 to attacli credence. 



If geographical distribution were sufficient to account for all the 

 changes which have taken place in climates, then, by coupling with 

 it, as Sir Charles Lyell has done, a decrease in the obliquity of the 

 Ecliptic, so as to diminish the polar circles and thereby abridge 

 those periods of darkness which, according to some geologists, 

 present an insuperable difficulty in relation to the fossil vegetation of 

 Greenland and Spitzbergen, we should appear to make some pro- 

 gress towards an explanation of the puzzle presented by the presence 

 of that vegetation ; but even in that case we should, as already 

 mentioned, have to assume a very much greater variation in the 

 obliquity than astronomers will concede, in order to meet the case 

 of such very high latitudes as Spitzbergen. We should also have 

 to satisfy ourselves that Mr. Croll's contention that a decrease in 

 the obliquity would increase the cold of the polar regions was 

 unfounded ; because, if otherwise, that decrease would neutralize 

 any increase produced in polar warmth by geographical changes ; 

 and so leave us without this essential desideratum for the growth of 

 the vegetation in question. 



As the influence of geographical causes, to a certain extent, on 

 climate is admitted by every one, from the features presented all 

 over the world, though the application of them in accounting for the 

 great changes in geological climates is disputed, it is not worth 



