248 THE LARCH. 



in countries only a little elevated above the level of 

 the sea, provided the atmosphere be not obscured by 

 fogs and constant cloudiness. 



" The constant dryness of the air of the Alps is one 

 of the causes which makes it prosper there. The 

 dampness of the air tends to diminish the evaporation 

 of the leaves, so necessary to that tree. You have 

 observed, and I had remarked it, that the larch does 

 not grow well near the sea. That proves what I have 

 just advanced. The sea produces an increase of damp- 

 ness in the air on two accounts: ist, like the surface 

 of fresh water, it exhales much water into the atmos- 

 phere ; 2d, the little watery particles which are 

 thrown out by the waves are carried here and there, 

 and deposited on all solid bodies ; they leave on them 

 a certain quality of salts, more or less deliquescent 

 (muriates of lime and soda), and these deposits con- 

 stantly attract dampness on those surfaces ; whence 

 it is that sea-dampness produces rust more actively 

 than any other dampness. 



" The want of a sufiQciently intense light, owing to 

 the obliquity of the solar rays, and to the opacity of 

 the atmosphere, and the overdamp state of the latter, 

 all appear to me permanent causes which, in your 

 climate, must predispose the larches to a state of watery 

 plethora, which is probably the cause of the destruc- 

 tion remarked in the heart of the wood. This cause 

 has little or no effect during the youth of the tree, be- 

 cause then its vegetation is vigorous ; but it goes on 

 increasing until the tree arrives at the age when, in 



