242 



THE POPULAR SCIENCE MONTHLY. 



shall represent the "covings" of the fireplace, and the base the front 

 line of the fireplace. From each front angle of the square carry a 

 line from D to C, to the " covings " or sides of the triangle, at an angle 

 of 45 with the front line of the fireplace. These two lines, with the 

 side of the square from which they are drawn, form the front of the 

 grid. The back line of the grid does not correspond with the cor- 

 responding side of the square, but is carried one and a half inch far- 

 ther back, so as to give greater depth to the grate, and allow the fire- 

 brick back to overhang the back of the grid to the extent of one and 

 a half inch (see A, Fig. 1) before it ascends as the " lean-over." 



|iffi, E 



A" 



D D 



I 2 S V S 6 7 8 



I I ! ' I I I 



Fig. 2. 



^ 



The diagram of the grate, with the square and triangle on which it 

 is based in dotted lines, will, I hope, make this description sufficiently 

 intelligible. Whenever a grate on this principle proves too hot for 

 a room, and in summer when a smaller fire is needed, the size should 

 be reduced in width by triangular fire-bricks at each side, which reduce 

 the fire-space to a square, with the addition of the one-and-a-half-inch 

 space under the back. This rule secures sufficient depth from front to 

 back, and a constant proportion between depth and width, whatever 

 be the size of grate. 



Rule IX. " The slits in the grating, or grid, should be narrow, 

 perhaps one fourth inch for a sitting-room grate and good coal, three 

 eighths for a kitchen-grate and bad coaV When the slits are larger, 

 small cinders fall through and are wasted. 



Rule X. u The front bars should be vertical, that ashes may not 

 lodge and look untidy ; narrow, perhaps one fourth inch in thickness, 

 so as not to obstruct heat and close together, perhaps three fourths of 

 an inch apart, so as to prevent coal and cinder from falling on the 

 hearth" (Fig. 3). It is too soon to judge as to the lasting powers of 

 one-fourth inch bars. Those in one of my own grates are round, and, 



