30 A B C OF THE STEEL SQUARE 



Ab; Jay off in the same way the same space from 

 Mie point B as Bd, Be ; also Cf , Cg and Db, DC. 

 Then draw lines ab, cd, ef and gh. Cut off the 

 solid angle E, also F, G and H. This will leave 

 an octagon, or eight-sided stick, which will be 

 found nearly exact on all sides. 



The board measure, known as the "Essex 

 Board Measure," Fig. 13, is made use of in fig- 

 uring these squares, and is used as follows : Fig- 

 ures 12 and 17 in the graduation marks on the 

 outer edge represent a one-inch board 12 inches 

 wide, which is the starting point for all calcula- 

 tions. The smaller figures under the 12 repre- 

 sent the length. 



A board 12 inches wide and 8 feet long meas- 

 ures 8 square feet, and so on down the table. 

 Therefore, to get the square feet of a board 8 

 feet long and 6 inches wide, find the figure 8 in 

 the scale under the 12-inch graduation mark and 

 pass the pencil along to the left on the same line 

 to a point below the graduation mark 6 (repre- 

 senting the width of the board), and you stop on 

 the scale at 4, which is 4 feet, the board meas- 

 ure required. If the board is the same length 

 and 10 inches wide, look under the gradua- 

 tion mark 10 on a line with the figure 8 before 

 mentioned, and you will find 6 8-12 feet board 

 measure; if 18 inches wide then to the right nn- 



