244 THE POPULAR SCIENCE MONTHLY. 



Rule XII. " The chamber under the fire should be closed by a 

 shield or economizer''" (G, Figs. 1 and 3). This has been already 

 spoken of, and described as the central principle which enhances 

 greatly the value of all the rest. 



Rule XIII. " Whenever a fireplace is constructed on these princi- 

 ples, it must be borne in mind that a greater body of heat is accumu- 

 lated about the hearth than in ordinary fireplaces. If there be the 

 least doubt whether wooden beams may possibly run under the hearth- 

 stone, then an ash-pan should be added, with a double bottom, the space 

 between the two plates being filled with artificial asbestus, ' slag-wool,'' 

 two inches in thickness?'' 



Rule XIY. " A fireplace on this construction must not be put up 

 in a party wall, where there is no projecting chimney -breast, lest the 

 heated back should endanger woodwork in a room at the other side" 



Having now worked up rules for the construction of an effective 

 fireplace, let us consider what benefits result. 



1. Economy of Fuel. I have already stated that my own experi- 

 ence of the application of the "Economizer" to all my original fire- 

 places, including kitchen and scullery, was a saving of more than one 

 fourth. Friends who have followed my advice report variously from 

 a sixth to one third. The saving in the Leeds Infirmary, according 

 to returns supplied to me by Mr. Blair, the general manager, has 

 been nearly a sixth, amounting to nearly one hundred tons in the 

 year. What the saving in the fireplaces constructed on the best rules 

 may be I can not say, probably about the same degree of saving, 

 with a large increase of heat given into the room. My conviction is 

 that such fireplaces make one ton of coal give out as much heat into a 

 room as two tons would yield if burned in the worst forms of the 

 nearly obsolete register-stove. 



2. Reduction of Soot. This is, perhaps, from a national point of 

 view, the most important point in connection with our subject and 

 yet it is the portion of it in which my evidence is the most defective. 

 I can only offer you my general impression that there is a very im- 

 portant reduction in the amount of soot, an impression based upon 

 observation of the smoke issuing from chimneys where " Economiz- 

 ers " are in use, and of the diminution of soot falling about my own 

 house, which is confirmed by the testimony of Miss Gordon, Lady 

 Superintendent of the Leeds Infirmary, as to the lessened amount of 

 soot which finds its way into the wards. 



3. Reduction of Ash-pit Refuse. This point is clearly proved by 

 the fine, snuff-like powder, free from cinders, which I show ; and by 

 the fact that the whole produce in the ash-pit of my kitchen fireplace 

 for one week was contained in one ash-pan, and weighed fifteen 

 pounds. 



Danger of Fire. Seeing that improved fireplace construction 

 involves increased heat about the hearth, an actual danger of fire will 



