636 
VENTILATION. 
openings between the window-frames and sashes., but by far 
the larger part is rapidly carried off by the flue of the 
chimney. 
This is the most powerful ventilator of the room, and con¬ 
tinually abstracts and removes a large stream of heated and 
vitiated air, sufficient to change the entire atmosphere of the 
room, provided there be an average amount of open doors, 
windows, and crevices, to yield a corresponding supply of 
pure air. 
So, also, Her Majesty’s Commissioners state that few 
persons are, perhaps, aware that an ordinary barrack fire¬ 
place removes a much larger amount of air than is merely 
required to dilute the carbonic acid and water to a healthy 
standard. The quantity varies, of course, with the section, 
height, and temperature of the chimney flue, and also with 
the force and direction of the wind. The extremes may 
be practically assumed at from 6000 cubic feet* per hour up 
to ten times that amount. 
Again, fresh air enters by windows, doors, and crevices. 
It has been estimated that eight cubic feet of air will pass 
per minute between each window-frame and the sashes. 
In the construction of stables it is, of course, necessary to 
have the usual appliances of doors and windows. But these 
should rather be considered as adjuncts to ventilation than 
part of the system itself. In any and every case the ample 
and free admission of fresh air, and the complete and ready 
escape of the contaminated atmosphere, which is all that can 
be desired or attained, should be self-acting. For even if we 
err, better that we err with too much than with too little pure 
air. 
This self-acting ventilation may, we think, be established 
by the three following combined plans. 
First, copious roof and ridge ventilators, with louver 
windows at the gables. This will allow of the heated air to 
escape. 
Secondly, a number of openings under the eaves, admitting 
fresh air, and aiding in the promotion of free circulation. 
Thirdly, the adoption of an intermural shaft of as great 
size as the thickness of the wall will permit, and intersected 
by a diaphragm, arising under the manger, about four courses 
of brick-work from the floor, and between every horse, each 
terminating externally above the roof. This would supply 
the place of a fire-place and chimney, furnish a large quantity 
of pure air in that part of the stable where it is most required, 
* Enough for five men. 
