Page:Popular Science Monthly Volume 29.djvu/254

242 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 corresponding side of the square, but is carried one and a half inch farther 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."



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.

"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 coal."—When the slits are larger, small cinders fall through and are wasted.

"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,