376 



On the Construction of Kitchen 



constitutes the cover of this boiler, may be made either 

 of tin or of sheet iron or of sheet copper; or it may be 

 made of cast iron. Whatever the material is of which 

 it is constructed, care must be taken to make it of such 

 dimensions precisely that its brim may enter the steam- 

 rim, and occupy the lower or deepest part of it, other- 

 wise the steam will not be properly confined in the 

 boiler. 



The following figure represents a vertical section, of 

 one half size, of the steam-rim of one of these boilers 

 (of cast iron), together with a section of a part of an 

 inverted shallow cast iron pan, which serves as a cover 

 to the boiler, and also of the circular covering of wood 

 which is attached to the pan, and defends it from the 

 cold air of the atmosphere. 



Fig- 45- 



In this figure the steam-rim is represented as being 

 full of water, and one of the screws is seen which fasten 

 the circular wooden cover to the inverted shallow pan 

 which confines the steam in the boiler. 



On examining the two preceding figures, it will be 



