recently carried on in the Russian Empire. 297 



physical truths requires the support of a material and external 

 interest — of an immediate application to the wants of social life ; 

 but when the sciences, without deviating from their noble and 

 primitive object, can boast of their indirect influence upon agri- 

 culture and the* arts of industry, (too exclusively called the use- 

 ful arts,) it is the duty of the natural philosopher to bring for- 

 ward the relations which exist between the study and the increase 

 of territorial wealth. 



A country which extends over more than 135 degrees of lon- 

 gitude, from the happy zone of the olive tree to the climates 

 where the soil is covered only with lichens, may advance more 

 than any other the study of the atmosphere, the knowledge of 

 mean annual temperatures, and what is more important for the 

 cycle of vegetation, that of the distribution of the annual heat 

 over the different seasons. Add to these data, in order to ob- 

 tain a group of facts intimately connected with one another, the 

 variable pressure of the air, and the relation of this pressure 

 with the prevailing winds and the temperature, — the extent of the 

 horary variations of the barometer, (variations which, under the 

 tropics, transform a tube filled with mercury into a kind of 

 clock with the most undisturbed movements) — the hygrometric 

 state of the air, and the annual quantity of rain, so important 

 to be known for the purposes of agriculture. When the varied 

 inflexion of the isothermal lines shall be traced by accurate va- 

 riations, and continued at least during five years in European 

 Russia and Siberia; — when they shall be prolonged to the 

 Western Coasts of America, where that excellent navigator, 

 Captain Wrangell, will soon reside, the science of the distribu- 

 tion of heat at the surface of the globe, and in the strata ac- 

 cessible to our researches, will rest on solid foundations. 



The government of the United States of North America, 

 deeply interested in the progress of population, and of the va- 

 ried culture of useful plants, has felt, for a long time, the ad- 

 vantages presented by the extent of its territory, from the At- 

 lantic to the Rocky mountains, from Louisiana and Florida, 

 where sugar is cultivated, to the lakes of Canada. Meteorolo- 

 gical instruments, compared with one another, have been dis- 

 tributed over a great number of points, the selection of which 

 has been the subject of discussion, and the annual results, re- 



