8 On tbe MOTION (/ 



formerly ; only {hewing a little more moiflure between the wood 



and bark. 



OBSERVATION i. The fap then on this clay, which was the 

 warmefl fince the ift of February, with bright fun-fhine, had 

 rifen a foot, or a little more, in the trunk of the tree, fo as to 

 bleed at an incifion. 



OBS. 2. At this incifion, a foot from the ground, the fap flowed 

 only from the wood. The bark, which was of a confiderable 

 thicknefs, was quite dry, and not a drop was formed till the 

 wood was penetrated. The moiflure between the wood and 

 bark was indeed confiderable, but not fufficient to bleed. 



EXP. 2. This day incifions were made upon another birch, which 

 was found to bleed copioufly, both in its trunk and branches. 

 The fap, therefore, in this tree was farther advanced, by feve- 

 ral days, than in that which was the chief objecT: of our ex- 

 periments. The latter rofe in one trunk, and flood in a thin 

 foil and expofed fituation. The former was a younger tree, 

 had a great number of luxuriant fuckers, confequently more 

 vigorous roots, and was placed in a deep rich foil, in a low 

 warm part of the wood. To thefe differences may be attri- 

 buted the more forward afcent of the fap in this tree above 

 the other. 



EXP. 3. A little pafl fix o'clock in the evening, when the fun was 

 fet, the two incifions which bled at mid-day were dried up ; 

 nor did the fap ifTue at a new incifion made a foot from the 

 ground. But an incifion made at that height in the other 

 tree, through which the fap was wholly difFufed, flill bled. 



MARCH 12.' 



Thermometer, at noon, 49. j at midnight, 41. 

 THE two loweft incifions bled as on the former day ; and the 

 third incifion, two feet from the ground, began to bleed for the 

 firfl time ; but the fourth incifion, and thofe above it, were flill 

 dry, as were all the branches. 



OBS. 3. 



