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year's wood, and as the tubes or vefl'els of wliich fucli newly formed 

 wood is compofed, are during the time of their growth not i'olid, but 

 of a very foft texture, this is the reafon why the bark can be fo eafily 

 llripped off in the fummer time. But that any part of the tree, ex- 

 cept that of die new growth, fliould be more fohd in winter than in 

 fummer, fecms to be altogether impofllble ; for it is plain to demon- 

 ftration tliat all trees are compofed of multitudes of fmall tubes or 

 veflels, which are formed every year by the tree's grov/th, and that 

 when once formed they preferve their fliape and fize, without any 

 alteration, although the tree be above an hundred years old. Thefe 

 tubes, which in all fcafons are filled with juices, are neither lefs in 

 winter nor larger in fummer, for the juice which circulates through 

 them is at all times the fame. But if it were polTible that the fub- 

 ftance of trees in v/inter could be more clofe or compadl, and in 

 fummer more fpongy or diftended, it would follow that the hard 

 and dead bark furrounding the tree would in winter be leparated 

 from the wood, and in i'ummer more fpiit open than it is found to be; 

 but fince we do not obferve this to happen in either inflance, it muft 

 be the better opinion, that timber felled in fummer is equally good 

 with that cut down in v/inter ; and if any one will take the trouble to 

 examine thole fmall chinks or fifl'ures which are produced in the bark 

 during the tree's growth in fummer, he will find that trees are not 

 increafed in their fize or fubftance in an hafly manner, but by very 

 €ow degrees. 





