134 STEPPES AND DESERTS. 



that from 1771 to 1824, the mean annual temperature has 

 hardly increased 1.2 Reaumur, (or 2.8 Fahrenheit), a 

 difference which is attributed to the increased size of the 

 town, to its greater population, and to the numerous steam- 

 engines. The difference may possibly be merely accidental, 

 for I find in the same period an increase of mean winter 

 cold, amounting to 0.9 Reaumur, or 2 Fahrenheit ; the 

 three other seasons had become somewhat warmer. Three- 

 and-thirty years' observations at Salem in Massachusetts 

 shew no alteration at all: the annual means oscillate, 

 within a degree of Fahrenheit, about the mean of the 

 whole number of years ; and the winters of Salem, instead 

 of having become milder, as supposed from the destruction 

 of the forests in the course of the thirty-three years, have 

 become colder by 1.8 Reaumur, or 4 Fahrenheit. (Forry, 

 p. 97, 101, and 107.) 



As the east coast of the United States is comparable in 

 respect to mean annual temperature in equal latitudes to 

 the Siberian and Chinese coasts of the old continent, so 

 also the west coasts of Europe and America have been very 

 properly compared together. I will only take a few 

 examples from the western region on the shores of the 

 Pacific, for two of which (Sitka in Russian America, and 

 Fort George, in the same latitudes respectively as Gotten- 

 burg and Geneva) I am indebted to Admiral Liitke's 

 voyage of circumnavigation. Iluluk and Danzig are nearly 

 on the same parallel, and although the mean temperature of 

 Iluluk, owing to its insular climate and to a cold 



