SURVEYING PRACTICE 3 



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 5| 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 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 



