The SAP in TREES. 17 



OBS. 17. At five o'clock in the afternoon, the ninth, eighth, and 

 feventh incifions had ceafed to bleed ; but ftill the inverted 

 branch, though placed above them, bled at the extremity, and 

 continued to do fo till it was dark, when all die other inci- 

 fions upon the tree were dried up. 

 To obferve the effects of an inverted pofition of the branches 



upon the motion of the fap, the two following experiments were 



alfo made : 



EXP. 6. On the iftof March, two branches of a birch, the one 

 placed five, and the other fifteen feet high, were tied down with 

 their extremities pointing directly to the earth. The buds on 

 thefe two inverted branches fwelled larger, broke fooner, and 

 threw out larger leaves, than any other buds upon the tree. 



EXP. 7. At the fame time, and in the fame manner, two other 

 branches of a birch were inverted, in every refpedl fimilar to 

 each other. All the extremities of the one were cut ; but 

 thofe of the other were left entire. That branch whofe ex- 

 tremities were cut, continued to drop at every twig during 

 the whole bleeding feafon ; yet the buds upon this branch 

 fwelled larger and broke fooner than thofe upon the other 

 branch, which had been fuffered to remain entire. 



COR. 10. From thefe experiments, I fhall only draw this obvi- 

 ous, though not unimportant conclufion, That wherever the 

 afcending fap moves moft freely, and in the largeft quantity, 

 there, the buds fwell to the largeft fize, and difclofe them- 

 felves foonefl. 



OBS. 1 8. At five this afternoon, the ninth incifion, eight feet 

 high, on the north fide of the tree, was dried up ; yet an in- 

 cifion, at the fame height, on the fouth fide, continued to bleed 

 till funfet, and was bleeding when the incifion, only fix feet 

 high, on the north fide, was become quite dry. 



COR. II. This obfervation fuggefts a fact, relative to the caufe 

 of the fap's motion, which deferves to be noted : That the 

 motion and bleeding of the fap does not proceed from a force 



C communicated 



