118 Desaiption of a Gauge . 



double the diameter gives double the circumference. The 

 allowance for bark is u?ually one inch in thirteen ; thai is, 

 if the greater circumference of a tree with ihe bark on, is 

 found to be thirteen inches, it is supposed it would be only 

 12 inches if the bark was taken oS, 



The instrument is composed of two straight pieces of well- 

 seasoned dtai, about thirteen feet long, joined together by 

 a pin going; through them, on ^hich they are moveable ; but 

 neither the length nor thickness is of any particular con- 

 sequence, as by following the directions hereafter given, 

 they' may be made of any size. A little way from the larger 

 end IS a brass limb I call the inoex, on which are engraven 

 fisrures denoting the quarter-girth in feet and inches. To use 

 •this in«triimtat, it is only necessary to take hold of the large 

 end, and apply the other to that part of the tree where you 

 wish to know the girth, opening it so wide as just to touch 

 at the same time both sides of it, without straining it, 

 keeping the graduated side of the index uppermost, on which 

 the greater girth will be ^hown, after allowing for the bark, 

 by the inner edee of the brass on the right hand leg ; — an 

 operation so easy and simple, that a person of the meanest 

 capacity might measure a great number of trees in a day. 

 ■ For taking the height of a tree, I would recommend deal 

 rods of seven teet long, made so as to fit into ferrils at the 

 end of each other, tapering all the way in the same manner 

 as a fish mo; rod A set of five of them with feet marked on 

 them, would enable a man quickly to measure a tree of more 

 than forty feet high, as he would be able to reach himself 

 about seven feet. 



The improvements it is capable of, are, making a joint 

 in the arch or scale, to enable it to shut up (when the legs 

 are closed) towards the centre, which would make it easier 

 to carry. Secondly, as it sometimes happens that standing 

 timber is sold without any allowance for bark, and at other 

 times with a less allowance than one incti in thirteen, two 

 other scales on ihe index mit!;ht be added in such cases, one 

 without any allowance, and the other to allow as might he 

 agreed on. 1 would have added these, but thought the 

 socieiy would rather see it in the state in which it has beerj 



tried 



