COMPASS AND PACING 
95 
shown in illustration is the pattern of the U. S. Forest 
Service. The base is flat so that the instrument may be 
used to orient a plane table — it is square also and gradu¬ 
ated on its edges with a protractor and two scales for draft¬ 
ing purposes; declination can be set off by means of a 
vernier; inside the box a pendulum is fitted and the staff 
mountings permit of turning the instrument and holding 
it edgewise while employed as a level or clinometer. 
Staff Compass 
A main use for the staff compass in topographical and 
timber work is for making foot traverses, a purpose for 
which it is thoroughly adapted. The common pocket 
compass with needle 1^ to 2 inches long, indeed, may be 
used for the same purpose, and when it enables a man to 
travel a mile with only 1° or 2° of angular swing, as it 
will do if carefully used, it deserves to be called a surveying 
instrument. 
Pacing. The pace has been long used as a check on 
short distances, but the real capacity of pacing as a method 
of measurement has only recently been developed. It 
is of special value to woodsmen who must travel their 
country over in any case, and who by a little extra pains 
taken in this direction can bring out much valuable infor- 
