458 



Correspondence. 



100 of carbonic acid, in order to form woody fibre, and 72.35 parts 

 by weight of oxygen which was in combination with the hydrogen 

 of the water, and which exactly corresponds in quantity with the 

 oxygen contained in the carbonic acid, must be separated in a ga- 

 seous form.* 



Again, the best soil for forest trees possesses a strong affinity for 

 water or its elements, and the shade afforded by the forest pro- 

 tects the moisture from evaporation in a great degree — ^even in the 

 decay of woody fibre there is every reason to believe, that decom- 

 position of water again takes place — whereas I am unaware of any 

 proof that forest has any power of attractions for the clouds, beyond 

 what its height may give it on extensive plains, and that could not 

 cause more rain to fall on northern aspects than on southern, in the 

 region we are talking of, as there are numerous points above the 

 region of forests that would, from their superior height, exert a superior 

 attraction. All my observations lead to the following conclusions ; 

 1st, that the snow lies longer and deeper on northern aspects, in con- 

 sequence of not being exposed for so long a time to the rays of the 

 sun ; 2nd, that forest grows more profusely on northern aspects, 

 owing to the fact, that the moisture on northern aspects is protected 

 from evaporation in a greater degree than on the southern. I am 

 glad to see that Captain Hutton also contradicts what I find to be a 

 very prevailing mistake, viz. that Chin-i, in Kunawur, is beyond the 

 influence of the monsoon, which is interpreted erroneously as being 

 above the region of clouds, and that no rain falls there. I got as 

 complete a ducking from rain as a man could wish, while I was 

 there, which demonstrated the error sufficiently to me. 



* Vide Liebig's Organic Chemistry of Agriculture and Physiology. 



