A B C OF THE STEEL SQUARE 111 



for any length, if the angle is right, and the 

 run equal. Should the brace be of great length, 

 however, additional care must be taken in the 

 adjustment of the square, for should there be 

 any departure from truth, that departure will 

 be repeated every time the square is moved, and 

 where it would not affect a short run, it might 

 seriously affect a long one. 



To lay out a pattern for a brace where the 

 run on the beam is three feet, and the run down 

 the post four, proceed as follows: 



Fig. 74. 



Prepare a piece of stuff, same as the one 

 operated on for four feet run; joint and gauge 

 it. Lay the square on the left-hand side, keep 

 the 12-inch mark on the tongue, over the gauge- 

 line ; place the 9-inch mark on the blade, on the 

 gauge-line, so that the gauge-line forms the 

 third side of a right angle triangle, the other 

 sides of which are nine and twelve inches, re- 

 spectively. 



Now proceed as on the former occasion, and 

 as shown at Fig. 74, taking care to mark the 



