486 REPOKT OF THE SECRETARY OF THE 



and on this subject investigators differ much.'' Becquerel 

 declares it certain that the removal of forest is accompanied 

 by an elevation of temperature. Boussingault states that in 

 plats of the same latitude and the same elevation above tho 

 gea, the forest exerts an influence equal to 2° F. But the ques- 

 tion of temperature is affected much more powerfully by the 

 mechanical influence of the forest, in impeding the fierce and 

 destructive currents of storms. Within the range of its influ- 

 ence the atmosphere may be comparatively quiescent, while 

 beyond the blast may be raging furiously. 



Now, upon the question of humidity, observes Stacht : 

 "As the lightning-rod abstracts the electric fluid from tho 

 stormy sky, so do forests attract rain from the clouds. The 

 forest, presenting an immense surface of evaporation, gives to 

 all the adjacent territory an abundance of rain and dew. 

 Forests, in a word, exert on the interior of a continent an 

 influence like that of the sea upon the climate of its islands 

 and coasts, watering the soil, and thereby insuring its fertility.**' 

 There is a pretty fable of old that gives the poetry of this phil- 

 osophy, — of the laurel of Ferro, that furnished sparkling 

 water to the inhabitants. The water flowed from its foliage, 

 drop by drop. Every morning the sea breeze drove a cloud 

 toward this wonderful tree, which attracted it to its huge top, 

 where it was condensed to a crystal liquid. But it is needless 

 to longer dwell upon the influence of so powerful an agency 

 as the forest growth of our State. It suflBces to remember the 

 fact, that by destroying the power of this agency, and counter- 

 acting its beneficent influence, the culture of certain fruits, 

 once possible over every part of our surface, is now confined to 

 the narrow lee of Lake Michigan. And this brings us to the 

 second agency already mentioned, — the great lakes that encircle 

 us. Upon what principle does their power depend ? Professor 

 Tyndall has responded to our query, by denominating it the 

 latent heat of water. Water is heated by the sun's rays with 

 exceeding slowness, but it also cools with equal deliberation ; 

 and in this cooling it gives out, in lowering of temperature. 



