SURVEYING PRACTICE 
23 
Thus with the case in hand. The tangent of the 
angle between the try-line and the true line has been fig¬ 
ured as .0107. This decimal multiplied by five chains 
or 500 links gives 5j links, the offset from the 5-chain 
point. Similarly 10 chains multiplied by .0107 gives 10.7 
links, and so on until all the offsets have been computed. 
By proportion the problem is even simpler. In the case 
in hand the offset at the 15-chain mark should evidently be 
half that at the finish, or 16 links. At the 5-chain mark it 
is J of it, or 5j links as found before. In the same way 
offsets for any length of line and any error in closing may 
be figured. When the points have been put in, the line 
may be blazed through by eye, or with the aid of the 
compass. 
3. Marking Lines and Corners 
Corners. Permanent corner marks are especially val¬ 
uable in maintaining bounds and protecting property 
rights; and the desirability of stone monuments, or, fail¬ 
ing these, of earth mounds, iron rods, or charcoal, is not 
to be disputed. Forest land is occasionally subject to 
great mischances, as from clean cutting, wind, and fire, and 
marks which can survive these have distinct and peculiar 
value. 
On the other hand, posts of durable wood, and trees that 
are likely to remain in place a long time are generally 
handiest, are easy to mark on, and frequently meet, better 
than more elaborate and expensive marks, the ideas of 
owners and the customs of the country. Supplemented 
by blazed and marked witness trees, such markings for 
corners are now in wide use on forest property and there 
can be little doubt that their use will continue. Marks on 
living trees should be placed in most cases on a peeled or 
blazed surface of the wood, though bark marks, much dis¬ 
torted it is true, have been known to remain legible for a 
very long time. 
Corners in every case should be plainly inscribed so that 
any interested person may readily identify them. It is 
usual in woods practice for the surveyor who establishes a 
