348 ACCOUNT OF THE ARCTIC EEGIONS. 



profound researches on the relations of air to heat 

 and moisture, and on the propagation of heat and 

 cold through the atmosphere to distant regions, has 

 contributed very largely to the advancement of me- 

 teorological knowledge, and to our information on 

 the properties of the atmosphere ; and, in his inven- 

 tion of a correct hygrometer, the action of which is 

 dependent upon known and calculable philosophical 

 principles, he has presented the meteorologist with 

 a gift, which, when more generally known and adopt- 

 ed, will afford results, on the dryness and dampness 

 of the atmosphere, as satisfactory as those on its tem- 

 perature and pressure. 



Such researches as these have not been made in 

 vain ; yet the knowledge of atmospheric phenomena 

 must remain in imperfection, until the relations to 

 each other, of heat, electricity, pressure, &c. the 

 principles on which these phenomena are supposed 

 to depend, be ascertained, and the laws by which 

 they are individually governed, be fully discovered. 

 But when we consider the difficulty of investigating 

 the characters and properties of principles so ob- 

 scure, and fluids so subtle as air, aqueous vapour, 

 electricity, light, heat, &c. there is reason to believe 

 that their various combinations and effects on each 

 other, will never be wholly elucidated. 



In the economy of Nature, we find that varying 

 and fluctuating phenomena are produced by oppos- 

 ing or counteracting forces or principles ; and that 



