577 
of Edinburgh, Session 1868 - 69 . 
vvich. The curved lines thus obtained, and of which a specimen is 
given under the northern hemisphere of the range chart, show the 
fluctuations of the temperatures forming the range lines of these 
amounts; the upper line shows the July , and the under line 
parallel to it the January temperatures, according to the scale 
shown at the side of the lines. 
From this we observe that the line of 60° range lies between 
the temperatures of 30° Fahr. in January, and 90° Fahr. in July 
at its maximum , in Persia, and between —20° Fahr. and + 40° Fahr. 
in Baffin Bay at its minimum. 
The line of 50° of range, again, has its maximum in Central Asia 
between 40° Fahr. in January and 90° Fahr. in July, and its 
minimum in the Arctic Sea between — 15° Fahr. in January and 
+ 35° Fahr. in July. 
Forty degrees of range stands highest on the temperature scale in 
Arabia and Persia between 95° Fahr. in July, and 55° Fahr. 
in January; and is at its lowest point between -=5° Fahr. and +35° 
Fahr. in the Arctic Sea. 
The line of 30° of range has its maximum in Central Africa be- 
tween 95° Fahr. and 65° Fahr. in July and January, and its mini- 
mum between + 5° and 35° in the North Atlantic. 
Lastly, the line of 20° of range is at its highest temperature in 
Central Africa between 95° Fahr. and 75° Fahr. in July and 
January, and at its lowest in North Norway between 47° and 27° 
Fahr. The next lowest temperatures on the line of 20° fall in the 
British Isles, between 38° in January and 58° in July at Braemar in 
North Scotland, and 42° in January and 62° in July at Ventnorin 
South England. 
The points on these lines which pass through the same iso- 
therms, or whose January and July temperatures are at the same 
heights on the scale, have, so far as regards temperature, exactly 
the same yearly climate. Thus, on the line of 60° of range we 
may compare Minnesota in the United States with South Russia ; 
on the line of 50° range, the Great Salt Lake region, in America, 
with the Caucasus in Europe; and the east coast of China in Asia, 
or the American Lake district, with that of North Russia. Again, 
on the line of 40° range, Newfoundland has exactl)' - the same 
climate as the Baltic provinces of Russia, and the coasts of 
