THE SCIENCE OF THE KITCHEN 



the various pieces. Put it together and light it. Cover the 

 air holes completely and then leave them wide open. What 

 difference does it make in the flame ? Cover the hole partially. 

 How should the burners on a gas range be regulated ? 



FIG. 32. Fireless cooker. 



Fireless cooker. The fireless cooker is another device 

 for cooking. It consists of a box with a tightly fitting 

 cover, in which are placed several receptacles separated 

 by some material which conducts heat slowly, such as 

 hay or excelsior. The foods to be cooked are first brought 

 to boiling on a stove, then 

 placed in these compart- 

 ments and tightly cov- 

 ered. As there is little 

 opportunity for the heat 

 to escape, the foods con- 

 tinue to cook, and if suffi- 

 cient time be allowed, they are cooked enough for eating. 

 Pies and bread may be baked and meats roasted. For this 

 purpose heavy plates are heated and placed in the bottom of 

 the compartment and the food placed on these. If one has 

 access to a gas range or a kerosene stove by which water 

 can be quickly heated, the fireless cooker has two great 

 advantages, comfort -during the warm weather, and the 

 saving of fuel. It is claimed also that food cooked slowly 

 and for a long time is more palatable than when cooked by 

 the ordinary method. 



Thermos bottle. The thermos bottle, in which liquids 

 may be kept either hot or cold for a long time, is made 

 on somewhat the same principle. It is virtually two bot- 

 tles, one inside the other separated by a vacuum, through 

 which heat cannot pass readily in either direction. The 

 outer surface is made of a bright, smooth material which 

 reflects the heat rays instead of allowing them to pass 

 through. 



