and the Economy of Fuel. 87 



the instant the door is opened, the cold air rushing with 

 impetuosity into the fire-place deranges entirely the 

 whole economy of the fire. Besides this, it is frequently 

 very disadvantageous to the process which is going on 

 to open the door of a fire-place, and it is always attended 

 with a certain loss of heat, and consequently should as 

 much as possible be avoided. 



I intimated that the window I have been describing 

 afforded me amusement : it did still more, it afforded 

 me much useful information, it gave me an opportunity 

 of observing the various internal motions into which 

 flame may, by proper management of the machinery of 

 a fire-place, be thrown, and of estimating with some 

 degree of precision their different effects. In short, it 

 made me better acquainted with the subject which had 

 so long engaged my attention, fire ; and with regard to 

 that subject, nothing surely that is new can be uninter- 

 esting. But to return to the brewery. To the top of 

 the boiler was fitted a curb of oak timber. The four 

 straight beams of which this curb was constructed are 

 each about 7 inches thick, and 1 5 inches wide ; and the 

 upper part of the boiler is fastened by large copper 

 nails to the inside of the square frame formed by these 

 four beams. From the top of this curb is raised a 

 wooden building, like the roof of a house with a double 

 slant or bevel, which serves as a cover to the boiler. 

 This building, the sides of which are about 3 feet high 

 inwards, and the top of which is covered in by a very flat 

 roof, slanting on every side from the centre, is con- 

 structed of a light frame-work of timber (four-inch deal 

 joists), which is covered within as well as without with 

 thin deal boards, which are rabbeted into each other 

 at their edges, to render the cover which this little 

 edifice forms for the boiler as tight as possible. 



