INSTRUMENT FOR MEASURING STANDIN3 TIMBER. 325 



ircnerally the case. When an estate is sold on which the " nIe ^ me*- 



■^ . sured at great 



timber is to be valued, I believe, there is no other way in expense. 



general use of finding the girth of a tree (which, being 

 squared and multiplied by its length, gives the contents) 

 than by actually getting up to the middle, where the girth 

 is usually taken, with a ladder or otherwise: a method 

 which is very troublesome and expensive where the quantity 

 is large. The seller has, therefore, noway, but at an enor- 

 mous expense, of finding the real contents of what he has 

 to offer, and as the buyer, if a dealer, from his knowledge 

 is able to form a more accurate judgment, it often happens, 

 that the seller sustains much loss. J have known it ex- 

 ceed 50 per cent. Having some time ago a large quantity 

 to survey, I thought it possible to invent an instrument, 

 which would obviate this inconvenience, and which might 

 be sold at a low price, be correct in its work, quick in ex- 

 ecution, and such as any capacity might use. I likewise 

 thought it might be so contrived, as to make such an allow- 

 ance for bark, as should be agreed on. The instrument I 

 send you possesses all these qualifications, and is susceptible 

 of several improvements, of which I was not aware when I 

 made it, which I will point out at the end of my letter. 



It is well known, that the diameter and circumference of 

 circles are in a certain proportion to each other, and that 

 double the diameter gives double the circumference. The Allowance for 

 allowance for bark is usually one inch in thirteen, that is, 

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

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

 12 inches if the bark was taken off. 



The instrument is composed of two straight pieces of well Measuring in- 

 seasoned deal, about thirteen feet long, joined together by scr ib e d. 

 a pin going through them, on which they arc movable; 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 index, on which are engraven 

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

 this instrument, 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 



