Fire-places and Kitchen Utensils. 223 



Each of the large boilers is furnished with a circular 

 wooden rim, 2 inches wide and . 2 inches thick, which 

 is accurately fitted to the brim of the boiler; and 

 a circular wooden cover, consisting of three pieces 

 of deal board attached to each other by two pairs of 

 hinges, closes the boiler by being fitted accurately to 

 the upper surface of its circular wooden rim. 



One of the three pieces of board, which together 

 form the flat circular cover of the boiler, is firmly fast- 

 ened down to the wooden rim of the boiler, by means 

 of two small hooks of iron ; and from the middle of this 

 part of the cover, so fastened down, a long tin tube, 

 about \\ inches in diameter, rises up perpendicularly 

 to the ceiling of the room, and carries off the steam 

 from the boiler out of the kitchen. 



As the cover of the boiler is composed of three flat 

 pieces of board united by hinges, and as the cover, 

 so formed, is merely laid down on the flat surface of 

 the wooden rim which is connected with the brim of 

 the boiler, it might very naturally be expected that 

 some of the steam would be forced through between 

 the joinings of the cover, or between the cover and the 

 wooden rim ; but this is what never happens. So far 

 from it, steam seldom comes into the room even when 

 the cover of the boiler is in part removed, by laying 

 back the first division of it upon the second, so strong 

 is the draught of the steam-tube. 



This phenomenon, which rather surprised me when 

 I first observed it, was of considerable use to me ; for it 

 led me to discover the utility of dampers in the tubes 

 or chimneys that are destined for carrying off the steam 

 from boilers, and more especially from such boilers 

 whose covers are not perfectly air-tight. If these steam- 



