The Climate of Great Britain. 117 



ture is not quite so low as at the Asiatic pole, the former tem- 

 perature being 3^°, the latter 1° Fahrenheit. 



Returning to our subject, let us consider the all-important 

 question of range of climate. The effects of climate, unim- 

 portant to the stronger inhabitants of a country, but largely 

 influencing the health and comfort of the majority, are chiefly 

 felt through the changes that occur during the year. Now, we 

 have seen that the line of mean annual temperature of England 

 departs in a very marked manner from coincidence with a 

 latitude-parallel ; but we shall find the lines indicating the 

 extreme temperatures of the year much more irregular ; and 

 the peculiarity of climate, which their conformation illustrates, 

 much more important. 



In Fig. 1 the isochimenal, or the line of equal winter heat, 

 through London, is indicated by a strongly marked closed 

 curve. Its form is remarkable. It passes nearly in a north 

 and south direction, along the length of England and Scotland, 

 approaches suspiciously near to Iceland, but turns sharply 

 southwards and travels across the Atlantic in a direction which 

 brings it to the American continent near Washington; still 

 approaching the tropics, it travels through the northern parts 

 of Texas, where it reaches its greatest southerly range. Pass- 

 ing gradually northwards to the neighbourhood of the Aleutian 

 Islands, it thence trends southwards again, passes through the 

 Corea, traverses the Asiatic continent nearly on the latitude- 

 parallel of Nankin ; thence travelling slightly northwards, it 

 crosses the southern part of the Caspian Sea, the Black Sea, 

 the north of Turkey, and passes through Venice and Paris to 

 London. On the continents the isochimenal falls outside (that 

 is, south of) the annual isotherm, while on the oceans the 

 reverse holds. The projection of the isochimenal thus appears 

 as an irregular oval, whose greatest length lies on the conti- 

 nents. 



We see here, again, the indication of a tendency to form 

 two curves, and thus of the presence of two poles of ex- 

 treme winter cold in the northern hemisphere. The isochi- 

 menals of greatest cold hitherto traced in the two continents, 

 are shown by two broken curves in Fig. 1. The cold of the 

 Asiatic curve is very much greater than that of the American, 

 the former curve marking a winter cold of — 40° Fahrenheit (72° 

 below freezing), the latter a winter cold of — 26° 5', only — if one 

 may apply such an adverb to a cold of 58° 5' below freezing. 

 Professor Nichol remarks that, "if a polar projection were 

 made of these regions for January, it would be found that the 

 two coldest spaces of these continents form a continuous band 

 passing across the pole of the earth." I cannot but think that 

 this is a mistake. I believe that if the isotherms traced, in 



