Heating, Ventilation and Lighting 



for the work required of them. The furnace should be 20 per cent, larger than 

 the actual figured size, and heating power should be carefully calculated before the 

 furnace is decided upon. 



The great fault with the system is the difficulty in driving the heated air against 

 the w r ind. With this in mind the allowance in size of the furnace, as stated above, 

 is advisable; also, the setting of the heater somewhat toward the point of strong wind. 



The principle of the delivery of heat is that hot air rises. Such being the 

 case, it is hardly to 

 be wondered at 

 that in low cellars, 

 where the pipes 

 instead of being 

 " pitched" are run 

 horizontally, the 

 delivery is not 

 satisfactory. Fur- 

 nace pipes should 

 be pitched I foot 

 to every 10 feet of 

 run, and no flat 

 run should exceed 

 20 feet; less if pos- 

 sible. 



It has been 

 suggested that the. 

 fresh-air duct be 

 carried through the 

 building, so as to 

 have two inlets and 

 thus avoid the pos- 

 sibility of the hot 

 air reversing and 

 following out 

 through the duct. 

 This is undoubtedly 

 a wise precaution, 

 but in any event 

 the duct should be 

 made of galvanised 

 iron to avoid leak- 

 age. It is well to 

 consider, too, the 

 advisability of pro- 

 viding for a supply 

 of cold air to mix 



With Warm in SUch Old mantel in the Ladd House, at Portsmouth, N. H. The Franklin stove is here shown 



