DOMESTIC FIREPLACE CONSTRUCTION. 237 



construction is the most simple, and which, of course, are the cheap- 

 est, are beyond comparison the best, on all accounts. Nothing being 

 wanted in these chimneys but merely a grate for containing coals, and 

 additional apparatus being not only useless but very pernicious, all 

 complicated and expensive grates should be laid aside, and such as are 

 simple substituted in their stead. In the choice of a grate, beauty and 

 elegance may easily be united with perfect simplicity. Indeed, they 

 are incompatible with everything else." Again he says, " Iron, and 

 in general metals of all kinds, are to be reckoned among the very 

 worst materials that it is possible to employ in the construction of a 

 fireplace." 



Rule II. " The back and sides of the fireplace should be of brick, 

 or fire-brick." Brick retains, stores, and accumulates heat, and radi- 

 ates it back into the room, and keeps the fuel hot. Iron lets heat slip 

 through it up the chimney, gives very little back to the room, and 

 chills the fuel. On this point also Rumford speaks very strongly. 

 "The best materials I have hitherto been able to discover are fire- 

 brick and common bricks and mortar. . . . The fuel, instead of being 

 employed to heat the room directly or by the direct rays from the fire, 

 should be so disposed or placed as to heat the back and sides of the 

 grate, which must always be constructed of fire-brick or fire-stone, and 

 never of iron or any other metal." 



Rule III. " The fire-brick back should lean over the fire, not lean 

 away from it" as has been the favorite construction throughout the 

 kingdom. The lean-over not only increases the power of absorbing 

 heat from rising flame otherwise lost up the chimney but the in- 

 creased temperature accumulated in the fire-brick raises the tempera- 

 ture of gases to combustion-point, which would otherwise pass up the 

 chimney unconsumed, and thus be lost. Rumford discovered accident- 

 ally the value of this " lean-over," and at once realized its immense 

 importance. He does not, however, seem to have earned out his in- 

 tention of working out for general adoption this form of back. 



He first of all condemns to alteration all fire-backs which lean away 

 from the fire. " It frequently happens that the iron backs of grates 

 are not vertical, but inclined backward. Where the grates are wide, 

 and can be filled up with fire-brick, the inclination of the back will be 

 of little consequence, since, by making the fire-brick in the form of a 

 wedge, the front may be made perfectly vertical, the iron back being 

 hid in the solid work of the fireplace. If the grate be too shallow to 

 admit of any diminution, it will be best to take away the iron back 

 entirely, and cause the vertical back of the fireplace to serve as the 

 back to the grate." 



He next describes his discovery of the value of the " lean-over " : 

 "In this case I should increase the depth of the fireplace at the hearth 

 to twelve or thirteen inches, and should build the back perpendicular 

 to the height of the top of the burning fuel, and then, sloping the back 



