Fire-places and Kitchen Utensils. 295 



cumference, in order that it may close the roaster with 

 accuracy; and it should be at least three quarters of an 

 inch larger in diameter than the roaster, in order that 

 no part of the circular plate of sheet iron, which should 

 be fastened to it by being turned over its' edge, may get 

 between it and the end of the roaster. 



Of the Blowpipes. 



There are various ways in which the blowpipes may 

 be fastened to the roaster. The common method, when 

 they are made of sheet iron, is to fasten them with rivets ; 

 but as blowpipes of sheet iron are liable to be burned out 

 in a few years, if much used, it is better to procure them 

 of cast iron from an iron founder, in which case they 

 should be cast with flanges, and should be keyed on 

 the inside of the roaster; and their joinings with the 

 bottom of the roaster must be made tight with some 

 good cement that will stand fire, and is proper for that 

 use. 



The effect of the blowpipes will be considerably in- 

 creased if a certain quantity of iron wire, in loose coils, 

 or of iron turnings, be put into them. These being 

 heated by the fire, the air which passes through the 

 tubes, coming into contact with them, will be more 

 heated than it would be if the tubes were empty ; but 

 care must be taken that the quantities of these sub- 

 stances used be not so great as to choke up the tube 

 and obstruct too much the passage of the air. 



The stoppers of the blowpipes must be made to close 

 them well, otherwise air will find its way through the 

 blowpipes into the roaster at times when it ought not 

 to be admitted. One of these stoppers, represented 

 on a large scale, is seen drawn a little way out of its 



