3 }4 hijluence of Snow and Ram 



diftiiiguiflied, unlefs by particular inftruments, or after a 

 feries of obfervations often repeated. When thefe trace- 

 have been obferved by a great number of individuals, for 

 fiveral generations, however incorrectly tranfmitted, and 

 however obfeure may be the tradition, the philofopher mnfl 

 beware of deciding too raihly. The greater the number of 

 obfervers, the more perfect is the uniformity of their opi- 

 nions reflecting the phenomenon, and the more careful 

 ought people to be in their difcuffions before they venture to 

 contradict- them, 



The influence of fnow on vegetation has been fubjected 

 to the examination of too many obfervcrs, to allow us to be- 

 lieve it poiiiblethat there conld be fo great an uniformity in 

 their opinions, were not the effects really fuch as are fup- 

 pofed. In this memoir, then, I ihall examine thefe effects $ 

 I ih all endeavour to explain the caufe of them, and fliall en- 

 quire what relation tberc is between the explanation given 

 ago by tanners and a more accurate analyfis of fnow. 

 tt, after a very cold and very fevcre winter, vegetation is 

 ftrongcr and more active in proportion as plants have been 

 covered with a greater depth of fnow is a certain facl, proved 

 by the refult of the experience of every one engaged in agri- 

 culture. The caufe is fimple and natural. All plants are 

 capable of fupportingcold in a lefs or a greater degree ; there 

 are fome which cannot be expofed to the temperature of 

 melting ice without pcrifhing, and there are others on which 

 the mod intenfc cold produces no alteration. Each plant 

 then has certain limits to its refiftance of cold ; a certain 

 temperature beyond which it cannot be expofed to it with- 

 out the danger of being frozen and deftroyed, Several 

 plants expofed to a temperature nearly equal to that which 

 muft congeal them do not perifh, but, by the iharpnefs of the 

 cold which they experience, contract a languifhing difeafe, 

 tiie effects of which they feel during the whole courfe of 

 their exiftenee. 



If we expofe to the action of great cold a feries of plants 



capable 



