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58 



Vegetable Staticksl 



Experiment XX. 



I provided me 6 Thermometers, whofe 

 ftcms were of different lengths, viz. from 

 18 inches to 4 feet. I graduated them all 

 by one proportional fcale, beginning from 

 the freezing point ; which may well be 

 fixed, as the utmoft boundary of vegetation 

 on the fide of cold, where the work of ve- 

 getation ceafes, the watry vehicle beginning 

 then to condenfc and be fixed ; tho* many 

 trees, and fome plants, as grafs, mofs, in* 

 do furvivc it 5 yet they do not vegetate at 

 that time. 



The grcatcft degree of heat, which I mark- 

 ed on my Thermometers, was equal to that 

 of water, when heated to the grcatcft de^ 

 rce, that I could bear my hand in it, with, 

 out ftirring it about. A degree of heat, 

 which is the middle, between the freezing 

 point, and the heat of boiling water, which 

 being too great for vegetation, may there- 

 fore be fixed , as the utmoft boundary of 

 vegetation, on the warm fide ; beyond which 

 plants will rather fade than vegetate, fuch 



a degree of heat fcparating and dilpcrfing, 



inftcad 









