306 Professor Hosking on Ventilation. 



sides and back except as to the joints in front. Let all communi- 

 cation between the chamber so formed about the back and sides of 

 the grate and the chimney flue be shut off by an iron plate, open 

 only for the register flap or valve over the fire itself. External air 

 is to be admitted to the closed chambers thus obtained about the 

 grate by a tube or channel leading through the nearest and most 

 convenient outer wall of the building and between the joists of the 

 floor of the room, to and under the outer hearth or slab before the 

 fire, and so to and under the back hearth in which sufficient hples 

 may be made to allow the air entering by the tube or channel to rise 

 into the chamber about the fire-box or grate. Openings taking any 

 form that may be agreeable are to be made through the cheeks of 

 the grate into the air-chamber at the level of the hearth. In this 

 manner will be provided a free inlet for the outer air to the fire- 

 place and to the fire, and of the facility so provided the fire will 

 readily avail itself to the abolition of all illicit draughts. But the 

 air in passing through the air-chamber in its way to the fire which 

 draws it, is drawn over the heated surfaces of the grate and it thus 

 becomes warmed, and in that condition it reaches the apartment. 



An upright metal plate set up behind the openings through cheeks 

 of the grate, but clear of them, will bend the current of warmed air 

 in its passage through the inlet holes, and thus compel the fire to 

 allow what is not necessary to it to pass into the room ; and if the 

 opening over the fire to the flue be reduced to the real want of the 

 fire, the consumption of air by the fire will not be so great as may 

 be supposed, and there will remain a supply of tempered air waiting 

 only an inducement to enter for the use of the inmates of the apart- 

 ment. An opening directly from the room into the flue upon which 

 the fire is acting with a draught more or less strong, at a high level 

 in the room, will afford this inducement ; it will allow the draught 

 in the flue to act upon the heated and spent air under the ceiling, 

 and draw it off ; and in doing so will induce a flow of the fresh and 

 tempered air from about the body of the grate into the room. 



The mode thus indicated of increasing the effect of the familiar fire, 

 and making it subservient to the important function of free and 

 wholesome ventilation, is not to be taken as a mere suggestion, and 

 now for the first time made. It has been in effective operation for 

 six or seven years, and is found to answer well with the simple ap- 

 pliances referred to. But it is the mode and the principle of action 

 that it is desired to recommend, and not the appliances, since per- 

 sons more skilled in mechanical contrivances than the author pro- 

 fesses to be, may probably be able to devise others better adapted to 

 the purpose.* 



* The appliances used by Mr Hosking will be found more fully described 

 in his " Healthy Homes," published by Mr Murray. 



