586 



EVERYDAY SCIENCE 



H 



It is safer to pack the container with some non-inflammable 

 material, such as asbestos. A cheap and easily obtained substitute 

 is small cinders sifted from soft coal ashes, which may be obtained 

 at the boiler house of any mill if soft coal is not used in your home. 



(Cinders from hard 

 coal are not quite 

 so good but will 

 serve.) Experi- 

 ments with soft 

 coal cinders made 

 by home econom- 

 ics specialists for 

 the United States 

 Department of Ag- 

 riculture showed 

 that this material 

 is very nearly as 

 satisfactory for 

 packing as crum- 

 pled or shredded 

 paper. 



The Metal Nest. 

 The insulating 

 material is packed 



Courtesy of U.S. Department of Agriculture. 

 FIGURE 10. LONGITUDINAL SECTION THROUGH 

 FIRELESS COOKER 



solidly into 

 container, as 



the 

 will 



Showing details of the construction: A, outside 

 container (wooden box, old trunk, etc.) ; B, packing 

 or insulating material (crumpled paper, cinders, etc.) ; 

 C, metal lining in nest ; D, cooking kettle ; E, soap- be described later, 

 stone plate, or other source of heat ; F, collar to cover go as | fi^ snugly 



, -, 

 metal 



insulating material ; G, pad or cushion for top ; , , , 



H, hinged cover of box or container. about the 



nest (Figure 10, C}. 



This nest should be of a trifle greater diameter than the cooking 

 vessel and deep enough to hold a hot brick or soapstone (Figure 

 10, E) under the cooking vessel. A galvanized iron bucket may 

 be used as a metal nest. Better still, a tinsmith can make a galvan- 

 ized iron can of the required size, with straight sides, a rolled rim, 

 and a flat cover (Figure 11, A and C). 



