SURVEYING 



25 



tract may be sketched on one page, and details of certain 

 parts on other pages. 



All field notes should be carefully recorded in a well- 

 bound, durable, and convenient field book. The standard 

 field book has pages about 4 by 7 inches, ruled in any one of 

 the several forms of ruling, and is substantially bound. 

 The notes should be neatly made with a hard pencil in order 

 that they will not blur with use. In the sketches, the cus- 

 tomary symbols employed in map making may be used. 

 These will be described later. 



Field Methods. In making a chain survey, it is to be 

 remembered that, since angles are not measured, more meas- 

 urements will be required. Many fields are rectangular, 



and their measurement is correspondingly simple. When 



the angles are not right angles they may be determined by 



measuring three sides of a triangle laid off in the corner, 



making two sides or the legs of the triangle coincide with the 



sides of the field. 



Marking Points in a Survey. In making a survey all the 



important points should be marked for future reference. In 



laying out fields and lots, some permanent mark should 



be set at the corners. If a corner 



post is not used, a stone or a 



block of concrete should be set in 



the ground and a cross chiseled on 



the surface to indicate clearly the 



point. Stakes of durable wood may 



be used to good advantage. The 



exact point may be indicated by driv- 

 ing a tack in the top of the stake. A 



stake two inches square is often 



used. The field notes describing the 



location of these points should be 



Fig. 7. Sketch showing 

 how a line may be laid off 

 at right angles to another 

 at a point A. 



