THE UNITED STATES, AND OF CHINA. 707 



the rocky mountains, than in the same latitudes 

 of Europe. For example, in the Canadas, Nova 

 Scotia, New Brunswick, and the states north 

 of 42, the mean of winter varies fro'm 14 to 34, 

 and sometimes falls 30 or 40 below during 

 the coldest days ; while the mean of summer is 

 from 64 to 70, and often rises to 95, or even 100 

 in the shade, during the heat of the day, making 

 the mean difference between winter and summer 

 from 50 to 36, and the annual extremes from 130 

 to 140. 



But in the middle states between 42 and 36, 

 where the mean of the year varies from near 60 

 to 50, that of winter is from 35 to 27, of summer 

 76 to 72, making the difference from 45 to 41, 

 and nearly double what it is in the middle and 

 southern latitudes of Europe, where the annual ex- 

 tremes rarely exceed 90, whereas in the middle 

 United States, they vary from 100 to 120. In the 

 southern states, the mean temperature varies from 

 about 60 to 70, while that of winter is from near 

 40 to 50, and the number of growing months from 

 seven to ten. In the middle states, they are from 

 six to seven, and above latitude 42, from four to 

 five. As for the rest, the extremes of temperature 

 diminish as we proceed from north to south in all 

 climatesof thenorthern hemisphere, ceteris paribus. 



At Pekin in the north of China, and lat. 39, 54', 

 corresponding very nearly with the parallel of 

 Philadelphia and Cincinnati, the mean tempera- 



