18 Forest Club Annual 



comes at a point 5 cm. from the end of the strap, as shown in the 

 sketch, the diameter being 5 mm. large enough to allow the in- 

 sertion of a surveying pin. The space occupied by the overlap- 

 ping within the meter unit of the boundary straps when all per- 

 forations are made at dm. intervals, space heretofore practically 

 disregarded in mapping, is here taken care of by having the dis- 

 tance between the center of the first and second perforations one 

 dm. in length plus one-half the width of the boundary strap which 

 would overlap on the meter unit. Thus the distance between the 

 first and second perforations is 1.065 dm. At each succeeding 

 dm. there is a similar perforation marking off a total of exactly 

 10 dm. within the mapping unit. For convenience in mapping, the 

 space midway between each dm. division is numbered, the num- 

 bers running numerically from one to ten. 



Strap B, i. e. the division strap, is 9 mm. wide and 1.033 

 meters long. The length within the mapping unit is the same as 

 that of the boundary straps which provide for a full square meter 

 within the unit. As a convenience in segregating the vegetation 

 on the proper side of the guide, the division strap in cross sec- 

 tion assumes the shape of a semicircle, except for that portion 

 whose surface is in contact with or extending beyond the bound- 

 ary strap. This portion is flattened in order that the strap may 

 be held quite securely. The upper or flattened surface is divided, 

 numbered, and perforated as follows : 10 mm. from either end 

 there is a perforation of 5 mm. in diameter leaving 1.013 meters 

 between these two perforations. Each dm. division within the 

 plotting surface is plainly marked off by grooves. Between the 

 perforation and first groove at either end there is a distance of 

 1.065 dm., which space is the same as the corresponding interval 

 of the boundary straps. t Midway between each is a number, the 

 latter running numerically from one to ten corresponding to the 

 numbers along strap A. All straps are made of flexible, non- 

 corrosive, nonreflecting steel or other stable material which is 

 practically free from contraction and expansion.* 



As stated, there is an extension of 5cm. from the last per- 

 foration to the end of each boundary strap. This projection 

 makes possible the placing of the corner stake at exactly the 

 proper angle and in the correct position with the intersection 

 and extension of the straps as a guide, a matter which greatly 

 facilitates the placing of the guide tapes for accurate future map- 



* Linen or cloth tape provided with eyelets, as well as the leather straps 

 with perforated holes, are usually used but only with fair success. These 

 materials contract and expand notably so the straps at one mapping are 

 liable to be of quite different length than at another. The metallic straps 

 are, therefore, much to be preferred. 



