214 



A DISCOURSE 



BOOK III. It is asserted, that the larger parts of these rings are on the south and 

 "^^""^^^^ sunny side of the tree, (which is very rational and probable,) insomuch, 

 that by cutting a tree transverse, and drawing a diameter through the 

 broadest and narrowest parts of the rings, a meridian line may be de- 

 scribed. 



The outer spaces are generally narrower than the inner, not only in 

 their narrower sides, but also on their broader, compared with the same 

 sides of the inner ; notwithstanding which, they are for the most part, 

 if not altogether, bigger upon the whole account. 



Of these spaces, the outer extremities in Fir, and the like woods, that 

 have them larger and grosser, are more dense, hard, and compact ; the 

 inner more soft and spongy ; by which difference of substance it is, that 

 the rings themselves come to be distinguished. 



According as the bodies and boughs of trees, or several parts of the 

 same, are bigger or lesser, so is the number, as well as the breadth of the 

 circular spaces, greater or less ; and the like according to the age, 

 especially the number. 



It is commonly and very probably asserted, that a tree gains a new 

 ring every year. In the body of a great Oak in the New-Forest, cut 

 transversely even, (where many of the trees are accounted to be some 

 hundreds of years old,) three and four hundred have been distinguished. 

 In a Fir-tree, which is said to have just so many rows of boughs about 

 it as it is of years growth, there has been observed just 07ie less im- 

 mediately above one row than immediately below. Hence some pro- 

 bable account may be given of the difference between the outer and the 

 inner parts of the rings, that the outermost being newly produced in the 

 summer, the exterior superficies is condensed in the winter. 



In the young branches and twigs of trees there is a pith in the middle, 

 which in some, as Ash, and especially Elder, equals or exceeds in dimen- 

 sions the rest of the substance, but waxes less as they grow bigger, and 

 in the great boughs and trunk scarce is to be found : this gives way for 

 the growth of the inward rings, which at first were less than the outer, 



