468 forestry Quarterly. 



was also true that in most cases the measurements taken had to 

 be converted into usable data by means of tables or diagrams, 

 which consumed time and implied a large possibility of clerical 

 error. 



With a full appreciation of the requirements of a practical 

 timber scale Messrs. Clark & Lyford, in collaboration with Mr. 

 E. L. Kinman, of Vancouver, have designed the instrument il- 

 lustrated herewith. The chief virtue of the instrument is its 

 simplicity and the fact that it is a direct reading instrument both 

 as regards the height and diameter measurements. 



The principle of the diameter measurement is that of two 

 parallel lines of sight. A telescope is mounted on a sliding rider 

 (a) which slides on a bar (b) which bar in turn slides on a base 

 bar (c). This enables the telescope to slide from left to right a 

 total distance of 42 inches and therefore to measure the diameter 

 of any tree of this size or under. Inasmuch as the breast-high 

 diameter is measured with a tape this is a sufficient range for 

 practical purposes. 



For the purpose of measuring up a tree or group of trees the 

 instrument is set on the tripod and levelled by means of the level- 

 ling head shown in the illustration in the usual way. 



On loosening the clamp screw (d) the bars may be revolved 

 so as to bring the instrument in position to measure any tree in 

 plain sight, regardless, of course, of distance from the instru- 

 ment. When the telescope is brought approximately in range 

 with the left side of any tree the clamp (d) is tightened and the 

 fine adjustment is made with the tangent screw (e). Having 

 brought the cross hairs in the telescope to the side of the tree 

 to be measured, the telescope is slid to the right till the cross hairs 

 reach the other side of the tree, and the diameter of the tree at 

 this point is then read direct in inches and tenth from the scale 

 on the bars, and is, of course, exactly equal to the distance the 

 telescope was slid along the bars. 



The device for measuring the height of any point measured for 

 diameter is equally simple and direct reading. The upright 

 standard (f), which folds out of the way when not in use, is 

 provided with two fixed pins (gg) and one moveable pin (h). 

 To measure a tree an assistant places a rod bearing two targets 

 exactly 10 feet apart aaginst the trunk. The cruiser then ad- 

 justs the eyepiece (i), which is mounted with eight universal 



