24 



avoided ; the fire only requires to be kept lighted for 

 two hours at night, and again for the same period in 

 the morning ; the water, when once heated, retaining 

 its temperature for a long time. In a small house the 

 apparatus can be constructed for £5 ; and in all, for 

 less than half the cost of hot-water pipes. The 

 saving in tan and labour is also very great ; in some 

 places tan costs 19s. per cart load, and where it is 

 cheaper, the trouble and litter incident to its employ- 

 ment, and the dangers of loss from fungi and insects, 

 of which it is the peculiarly fertile foster-parent, ren- 

 der it objectionable as a source of heat. And when- 

 ever the tan has to be renewed, the trouble and de- 

 struction of plants is always great. 



In the following sketch, for which, as well as for 

 the next, we are indebted to Mr. Rendle : — A is a 

 transverse section of Roger's conical boiler ; B is the 

 fireplace ; g, the tank ; c, the flow-pipe ; d, the pipe 

 by which the water returns to the boiler ; e, is the 

 hole for the smoke, which, joined to a flue, /, can be 

 made either to ascend the chimney at once, or to pass 

 round the house. 



