m 
Distribution of Heat over the Globe. 
tern is prodigiously increased by the excessive heat of summer ; 
and it is undoubtedly to this cause that we must, in a great 
measure, ascribe the difference in the propagation of the yellow 
fever, and the different forms of the marsh fever, under the 
equator, and in the temperate zone of the New World On 
high mountains in islands of little extent, and along the shores, 
the lines of annual temperature take nearly the same form as in 
warm climates, having only a less degree of curvature. The 
difference between the seasons, too, becomes smaller. At the 
North Cape, in 71° of latitude, and in the isothermal line of 
it is almost 11° greater than at Paris, in 49° of latitude, 
and in the isothermal line of 50°. The sea-breezes and the 
fogs which render the winters so temperate, dimibish at the 
same time the heats of summer The characteristic of any 
climate is not the difference between the winters, expressed in 
degrees of the thermometer; — it is this difference, compared 
with the absolute quantities indicated by the mean temperature 
of the seasons. 
II. Difference between the Winters and Summer Sy in following 
the same Isothermal Line from West to East 
The differences between the seasons of the year are less great 
near the convex summits of the isothermal curves, where these 
curves rise again towards the North Pole, than near the concave 
summits. The same causes, which affect the inflexion or the 
greatest curvature of the isothermal lines, tend also to equalise 
the temperatures of the seasons. 
The whole of Europe, compared with the eastern parts of 
America and Asia, has an insular climate, and, upon the same 
isothermal line, the summers become warmer, and the winters 
colder, in proportion as we advance from the meridian of Mont 
Blanc towards the east or the west. Europe may be consider- 
ed as the western prolongation of the old continent ; and the 
western parts of all continents are not only warmer at equal la- 
titudes than the eastern parts, but even in the zones of equal 
annual temperature, the winters are more rigorous, and the 
summers hotter on the eastern coasts than upon the western 
coasts of the two continents. The northern part of China, like 
* Political Essa^ on the Kingdom of New Spain, tom. iv. p, 528, 
j* Leopold von Buch’s Travels in Lapland, tom. ii> 
