( 2 ) 



thick part of the ftem the rifing fap leaks or oozes out, and in this 

 liquor I have often, in the fummer time, obfcrved various animal- 

 cules, but which animalcules I could by no means conceive to have 

 illued from the wood; but rather, that the firft rudiments of them 

 had been depolited either by the rain or dew. 



At fig. 4, ABCD, is pi(5lured a fmall particle of Beech, to the 

 naked eye appearing of the fize reprefented at F ; the length of this 

 figure alfo fliews the thicknefs acquired by the tree in one year's 

 growth, the beginning and ceallng of which growth plainly appear 

 at the letters A D or B C. 



In this wood are two forts of perpendicular veflels, large and fmall 

 ones ; and, I am inclined to think, that there are alfo two forts of 

 horizontal ones, very minute, one fort of which appears at E E E, 

 lying in fmall numbers together, and when cut tranfverfely they 

 are fhewn in ^jg-. 5, at the letters H H H. 



The other fort lie in detached parcels, and are fhewn lengthwife at 

 D C; thefe veflels are alfo very fmall in comparifon with the perpen- 

 dicular ones, and are compofed of large clufters colle6led together, a 

 reprefentation of them when cut tranfverfely may be feen irijig. 5, 

 at I I. 



K K K K, are the large perpendicular vefl"els cut longitudinally; 

 and thele I have almoft always obfei-ved to be covered with par- 

 ticles which, viewed by a common magnifier, exhibited the appear- 

 ance of globules. 



Fig. 0, ABC D, is a fmall piece of Willow, to the naked eye ap- 

 pearing of the fize fhewn at F ; this wood confifls of two forts of 

 perpendicular veflels, fmall and large ; the large ones are covered with 

 particles bearing the appearance of globules, and in thefe I obferved 

 Certain oblique flreaks, which I long ago concluded to be valves*: 



* The author's opinion rcfpefting <he probable ufe of valves, in the veflels of trees 

 may be feen iu his Effay on the Oak, vol. I. p. 1 



