Dr. Forry on the Climate of the United States, 4*c. 43 



of the central provinces of Spain, in which, though at an eleva- 

 tion of two hundred feet above the sea, ice is an extremely rare 

 occurrence." 



Now, at Philadelphia, on an average of thirty two years, the 

 mean summer temperature is only 73°-i7 and that of winter is as 

 high as 32°-96, making a difference of 40°-21. Hence, as this 

 difference is nearly 15° less at Philadelphia than at Pekin, and as 

 the same result appears in the subjoined comparison of similar 

 parallels in Oregon and in western Europe, it follows, contrary 

 to general, indeed we may say universal, opinion, that the new 

 world, so far from having a climate more austere than the old, 

 has in fact, if there really exists any difference, a more mild and 

 uniform temperature. 



It is only within the temperate zone, from 30° to 60° of north 

 latitude, that the year exhibits the grateful vicissitudes of the 

 four seasons — the varied charms of spring and autumn, the tem- 

 pered fires of summer, and the healthful rigors of winter. Wis- 

 dom desires not that "eternal spring," the want of which poets 

 affect to deplore. At the equator there is no difference between 

 the mean temperature of summer and winter, but it increases, as 

 a general rule, with the latitude. From Florida to Canada, the 

 contrast in the seasons increases in proportion as the mean annual 

 temperature decreases — a general law subject to modification on 

 every parallel, in accordance with the varieties in physical geog- 

 raphy. It has been already seen, that the greatest and the least 

 contrasts of winter and summer are exhibited at Fort Snelling 

 and Key West. Upon this point, Humboldt has, as usual, de- 

 termined many important laws. 



" The winters of the isothermal curve of 68°," he says, "are 

 not found upon that of 51°, and the winters of 51° are not met 

 with on the curve of 42°." In considering separately what may 

 be regarded as the same systems of climate, for example, the 

 European region, the transatlantic region, or that of eastern Asia, 

 the limits of variation become still more narrow. Wherever in 

 Europe, in 40° of longitude, the mean temperature rises — 



To 59° -00 

 " 54° -50 

 " 50° -00 )> 

 " 45°-50 

 " 41°-00 



the winters 

 are from 



'44' 



•60to46°-40l 

 •50to41°-00 



and the 



73°-00to75°-00 

 68°-00to73°-00 



10 to 37°-40 }■ summers <! 62°-60 to 69°-80 

 28°-40to36°-10 from 57°-20 to 68°-00 

 20° -30 to 26° -80 55° -40 to 66° -00 



