INSTRUMENTS USEFUL TO A WOODSMAN. 145 
multiplies this value by his horizontal distance from the tree, 
which gives the height of the tree from the ground to the level of 
his eye. The figures thus secured are added together, giving the 
total height of the tree. Cost, $13. 
The scales of the instrument are sometimes graduated in tan- 
gents or percentages of angles instead of in degrees, in which case 
the table of tangents is not needed. : 
A number of other height measures are used in Europe, butafull 
description of them is not given, as that would make this Hand- 
book too voluminous. The most important instruments are the 
Brandis height mcasure, the Weise height measure, the Christen 
height measure, the Klaussner height measure, and the Winkler 
height measure. 
Several instruments have been devised to measure the diameter 
of a tree at any desired height. They are of practical use when 
extremely accurate measurements of standing trees are desired, 
but will probably not be extensively used by timber cruisers. The 
names of these instruments are the Breymann dendrometer, the 
Winkler dendrometer (combined with the Winkler height meas- 
ure), and the Wimmenauer dendrometer. 
CALIPERS FOR MEASURING DIAMETERS. 
Calipers are supplied to the trade in a variety of forms, but the 
form shown in fig. 13 is reeommended for its simplicity. It con- 
sists of a beam having a scale on both sides, graduated in inches 
and tenths. This beam is provided at one end with an arm held 
- in place by a bolt and nut which permit it to be detached for con- 
venience of transportation. The beam is provided also with a 
slidingarm fitted loosely, so astosldeeasily overit, but constructed 
so that when pressure is applied to its inner edge, as when it is 
brought against a tree trunk, it swings into a position in which 
it is ata true right angle to the beam. : 
For use in Eastern forests the most convenient caliper is one 
having a beam measuring 36 inches and arms half that length. 
Cost, $4. In forests where trees over 3 feet in diameter occur, 
a caliper having a beam measuring 50 inches and proportionately 
long arms should be used. 
Care should be taken to secure calipers made of perfectly sea- 
soned wood, for otherwise they will warp. Calipers graduated te 
show the contents of logs in board feet or cords are being intro- 
duced in many sections of the country. 
: 27824—Vol. 1, No. 36—02—10 
