DOMESTIC ECONOMY OF FUEL. 301 



oven, hot-plate, and front of the fire. For this reason, the combined 

 apparatus can never be so economical in fuel as separate apparatus ; 

 while, however, apparatus of this class, if not very carefully worked, 

 waste fuel, they, to some extent, save trouble to the cook. 



I have already mentioned several points of detail where fuel could 

 be saved in our kitchen-ranges, viz., by great attention to the close 

 fitting of the ash-pit and fire-grate doors, the use of double covers to 

 saucepans and boilers, the use of sand on the hot-plate to prevent the 

 escape of so much heat from that part ; and, beyond these, an impor- 

 tant point in securing economy is the separation of those culinary pro- 

 cesses which require different gradations of heat. The three main 

 parts of the ordinary cooking apparatus are the oven for baking and 

 roasting, and the bbiler, and the hot-plate. If the boiler is to be of 

 the form most effectual in saving fuel, the flame and gases from the 

 fire should play under and round every part of it ; the water should 

 be kept at something under 212, so that the gases, after leaving the 

 boiler, may not enter the flue much above that temperature, and, inas- 

 much as that is a higher temperature than is necessary for the purpose 

 of producing a sufficient draught in an ordinary chimney, the heat in 

 these gases should be still further utilized. In the first place, they 

 should be used to warm the water which will be required to replace 

 what is drawn off from the boiler ; and, in the second place, an econo- 

 my can be obtained by employing the gases, which pass off into the 

 chimney at a temperature above what is required for creating an effi- 

 cient draught, to warm the air supplied to the fire for purposes of com- 

 bustion. The experiments which I have made on the supply of warmed 

 air to feed the fire have, unfortunately, not been worked out sufficiently 

 to enable me to give them in a clear form with exact results ; but an 

 economy of from six to nine per cent, might be obtained from this 

 source. 



Then, as regards the oven. The baker's oven, of fire-brick, in which 

 the fire is made inside the oven, and the whole heat retained in and 

 reflected back from the sides and top and bottom, is a very economical 

 instrument when in continual use. With iron ovens, attached to a 

 kitchen range, the case is different. An oven which roasts requires a 

 temperature of from 400 to 450 at least. Therefore, to maintain this 

 temperature, the gases must pass off into the flue at a temperature 

 even higher ; when the oven is a roaster, a considerable volume of air 

 is being continually passed through it to carry off the steam from the 

 meat. This air, if admitted cold, as is the case with many ranges, acts 

 so as to cool down the interior, and therefore additional fuel has to 

 be consumed to counteract this cooling-down process. Now, however 

 good may be the conducting power of the material used for ovens or 

 boilers, a coating of soot diminishes the conducting power very rap- 

 idly, and consequently the temperature of the flue conveying heat to 

 the oven will always exceed that of the inside of the oven. It is, there- 



