£38 Influence of Snow and Rain on Vegetation, 



A very confiderable number of the plants which we have 

 the art of appropriating for our nouriihment and our want? 

 arefown in the months of Vendemiaire, Brumaire, and even 

 Frimaire (end of September to end of December) ; feveral 

 of thefe feeds oerminate before the cold commences its aftion 

 upon them and changes the principle of their life. The 

 fnow which covers the reft, acting on the germ by its oxy- 

 genation, obliges them to expand and to increafe the num- 

 ber of ufeful plants which the farmer and gardener commit 

 to the earth, and confequently to multiply their productions. 

 Here then we have three effects of fnow upon vegetation, 

 all very different, which contribute each fcparately to in- 

 creafe, every year, the number of our plants ; to give them 

 more vigour, and confequently to multiply our crops. Thefe 

 effects are : 1. To prevent the plants from being attacked by 

 the cold, and from being changed or periihing by its force. 



2. To fumifh vegetables with continual moifture, which 

 helps them to procure thofe fubftances neeeffary for their 

 nutrition, and to preferve them in a ftrong healthy ftate. 



3. Tocaufea greater number of feeds to germinate, and con- 

 fequently to increafe the number of our plants. 



Before I conclude, I muft mention fonle important expe- 

 riments, in regard to vegetation, which I made on rain- 

 water. Rain-water does not act on tincture of turnfole or 

 on fulphat of iron like fnow ; from winch it would appear 

 that it does not participate in that property which it acquires 

 by oxygenation. Rain-water, however, contains oxvgen 

 alfo ; but in a ftate of folution, and not of combination, as in 

 fnow; for under an exhaufted receiver rain-water fuffers 

 air to efcape from it, which contains proportions of oxygen 

 much greater than river water, fpring water, and even 

 atmofpheric air. 



Atmofpheric air expofed to the action of phofphorus, 

 without the application of heat, after the method indicated 

 bv Berthollet, is diminifhed in its bulk 0-20 ; that is to fay, 

 the phofphorus takes from the azot 30 parts of oxvgen in 



100 



