454 Forestry Quarterly 



while the station was occupied, this could also be scratched on 

 the poster. 



There are very few points where it is necessary to put up a 

 high signal, nor is it necessary to use large size poles. The best 

 size pole is about 4 inches in diameter and 10 feet long. It is 

 difficult to set high poles solidly enough. If high ones are needed 

 in order to increase the visibility, a slender pole can often be 

 used. On timbered summits or wherever a tree can be used 

 which will increase the visibility, the signals may be tacked to a 

 dr}^ pole which is nailed to the top of a tree. Sometimes the pole 

 can be tied up with rope to hold it in place until it can be nailed. 

 It was almost always necessary to trim ofif some of the top 

 limbs to make the flags clearly visible. 



The most satisfactory form of notes was like the sample given 

 below. The book was the standard form 289. which is very 

 handy to carry. Lengthy descriptions were often necessary, and 

 this form made them possible, as well as making a record of all 

 observations and computations for each point in one place con- 

 venient for checking. A field glass aids materially in the descrip- 

 tion of a new point. A careful description is necessary, both as 

 a matter of record and to insure any point being recognized 

 when viewed from other stations. 



When two points on the map are close together, the alidade 

 cannot be set accurately for a back sight. If it is known that a 

 point near at hand is to be occupied while the table is in position 

 the line may be extended and this extension used, or two needles 

 set on the extended line. This eliminates the error in platting 

 with a short base. 



Often it is possible to get the direction of a part of a stream 

 or ridge before enough points have been located to complete 

 it. That is, from a point, streams or ridges coincide in part with 

 a sight along the edge of the alidade, and their direction may 

 be sketched. 



If several extra sheets of paper are carried constantly in the 

 case for the large plane table, they become very thoroughly sea- 

 soned and are, therefore, less affected by changing conditions 

 of the atmosphere. 



Wilson, in his "Topographic Surveying," recommends setting 

 the needles in sealing wax. If no wax is obtainable, the needle, 

 after the head is broken ofif, may be set in a block of hard wood, 



