332 M. Humboldt on the Difference of the 



erroneous results. The large and classical work on the Canary 

 Islands, for which we are indebted to Mr Leopold Von Buch, 

 has now also filled up this blank, in the same way as his travels 

 in Lapland and to the most northern promontory of Europe, 

 first furnished us with a clear illustration of the causes which, 

 in the Scandinavian peninsula, beyond the polar circle, diminish 

 the severity of the winter cold, and preserve to the springs the 

 temperature which they had received from deeply seated strata, 

 and which occasion, under the influence of a continental climate 

 and that of the coast, an unequal elevation of the snow line, and 

 of the upper limit at which different species of trees grow. 



If we follow the current of the sea, which traverses the 

 great valley of the Atlantic Ocean, from east to west, we find 

 almost unexpectedly rich sources of instruction in the New 

 World, from Russian America, and the settlements of the 

 Canadian hunters, to the River La Plata, and the most southern 

 parts of Chili. It is no longer foreign naturalists who commu- 

 nicate to us the notices they have been able to collect during a 

 short residence in plains, rich in wood and grass, and on the 

 ice-covered ridges of the Cordillera ; we have no longer need to 

 judge of the mean temperature of the whole year by that of 

 single months or weeks ; here we obtain every where solid and 

 complete information from the inhabitants themselves. 



The executive power of the United States of North America 

 has ordered meteorological observations for five years to be made 

 three times a day, at seventeen different points, occupied by mi- 

 litary garrisons, between the 28° and 47° lat.^ between the Mis- 

 souri and the AUeghanys, the lake Michigan, and the coast of Pen- 

 sacola ; and from these observations, the average temperature of 

 days, months, and of the whole year, is drawn. These obser- 

 vations calculated by Mr Lovell, surgeon-general of the army, 

 have been published at the expense of the American govern- 

 ment, and have been distributed to all scientific institutions in 

 Europe. If this excellent example was followed in the eastern 

 part of our continent, and if, by the command and at the ex- 

 pence of a powerful monarch, similai* comparative theometricai 

 observations were carried on in well selected points in the ex- 

 tensive district situated between the Vistula and the Lena, the 



