DOMESTIC FIREPLACE CONSTRUCTION. 



241 



be fouDd such as an angle of 60 but commencing a few inches 

 above the fire so as not to lower the angle B where the lean-over 

 returns to the chimnev. 



. 1 2 3 4 S 6 r 8" 9 10 II 1/2 laches. 

 -^ / fiot. -^ 



FlQ. 1. 



Rule VIII. "The shape of the grate should be based upon a square 

 described within an equilateral triangle, the size to vary in constant 

 proportion to the side of the square" (Fig. 2). The shape of the grate, 

 or grid, is arrived at in the following way : Describe a square, D, of 

 which the sides shall be eight, nine, or ten inches, according to the size 

 of the room, within an equilateral triangle, E, the two sides of which 



TOL. XXIX. 16 



