SURVEYING 



29 



India ink, and a pen, a pencil, an eraser, thumb tacks, etc. 

 A bottle of carmine ink is convenient but not necessary. 

 When angles are to be plotted a protractor is quite necessary. 

 A good quality of drawing paper should be used, or one 

 that will stand reasonably hard usage in folding and handling. 

 A good quality of paper is known as bond paper, and a con- 

 venient size of sheet is 18 by 24 inches. A drawing made on 

 this bond paper may be reproduced by blue printing, a 

 process similar to the making of photograph prints from 



Fig. 11. A set of drawing instruments, consisting of a drawing 

 board, a T square, a triangular scale, two triangles, a protractor, 

 a case of instruments, an irregular curve, paper, ink, tacks, etc. 

 This sft is more complete than is required for map making as indi- 

 cated in text. 



negatives. The process is rapid, requiring but a few min- 

 utes, and the cost of the blue-print paper is but a few cents per 

 yard. A better print can be obtained, however, from a 

 drawing made on tracing cloth, which is thin and so prepared 

 as to make it practically transparent. Where expensive 



