338 



Two different 

 Stripes in the 

 wood. 



/ LeatheTlike 

 strings of the 

 bastard grain. 



ON THE STEM OF TREES. 



The sap is the nourishment those vessels convey ; it is a 

 thin waterish liquor, which is probably the juices of the 

 earth, medicated into this form, as most suitable to the life 

 it is to support. I suppose it is different in each different 

 soil ; but though I have often tried " by separating the 

 wood from the rest of the stem, and then macerating it, to 

 draw forth the liquor from the same tree in different soils," 

 I never could perceive there was the change one should 

 naturally expect. 



On dissecting the wood ; two different kinds of stripes 

 present themselves, some circular, an additional one being 

 each year added, which timber merchants call the silver 

 grain; and another from the circumference to the centre, at 

 least from the first line of the wood to the pith, which they 

 call the bastard grain. The first is the yearly stripe, and 1 

 had an opportunity in a large wood that was felled of ob- 

 serving the truth, not only of one stripe being added each 

 year, but that the stripe was large or small, according to 

 the exposure of the tree, and the favourableness of the 

 season. The wood had been planted at two different times, 

 one part 88 years, and the other 56 ; and each tree was 

 exactly marked according to its age, except three or four 

 which gave not the number of stripes specified, and were 

 afterward proved to have been planted instead of others, 

 that had been broken and cut down. In exposed situations 

 the west side was much narrower in several of the trees ; 

 and in the forwarder trees the N. and N. E. was the most 

 crowded, I mean, that in measuring the diameter of the 

 wood, it was less on one side of the circumference, than on 

 the other. In several trees there was sometimes only a half 

 circle; and in three different oaks, a rotten part having 

 caused the line of life to leave its situation, part of the pith 

 had followed it, and it had formed two piths, with many rows 

 of wood between. The bastard stripe consists I think of 

 two lines, or strings, with a little scale between them ; and 

 they appear from their extreme susceptibility to be formed 

 of the same leatherlike substance as the spiral vessels. 

 Mr. Knight is of opinion, that they are scales only, and he 

 is too exact an observer to be contradicted lightly ; but as he 

 mentions their pressing close (which they certainly do) to 



the 



