WAEMING AND VENTILATION. 283 



Cubic feet. 



April 4, 1866 367, 600 



April 0, 1866 430,000 



Mean 398, 800 



wbich corresponds to a total renewal almost eight times an hour. 



By means of this active ventilation, the temperature in the room has 

 been maintained till 10 o'clock at night at 67° to 70° at 5 feet above the 

 floor, and at 75° on an average at the ceiliug, while, before the introduc- 

 tion of the meaus of ventilation mentioned above, it was, respectively, 

 at the same heights, 80° and 90°. 



Q5. Flans to he adopted in schools already huilt. — It too often happens 

 that no plan has been provided in schools, and especially in night-schools, 

 to produce even a partial change of air or to regulate the temperature, 

 so that a stay in them is as unhealthful as it is unpleasant. There is, 

 then, as we have said, no resource but to open the windows, and this is 

 both uncomfortable and injurious to the scholars seated near them. 

 These defects may, however, be removed, at least in part, in most cases 

 by adopting the arrangements described in §64 in the case of a drawing- 

 school. 



In order to carry off the hot gases arising from the lights, and pre- 

 vent them from affecting the scholars, ventilating-openiugs shonld be 

 placed near the ceiling. A number of ventilatiug-flues should be cut, 

 the size of which may be calculated by the preceding rules; if possi- 

 ble, making them so large that the air may be renewed four or five 

 times an hour. If, however, it is only i^ossible to make one flue, it 

 should be connected by means of a horizontal pipe, with a series of ori- 

 fices in oue of the long sides of the room. At the bottom of tliis flue 

 should be placed either a little grate or three or four gas-burners, each 

 consuming about four cubic feet an hour, in order to keep up the draught 

 when the external temperature is too high for natural ventilation to be 

 effective. The use of gas is in most cases of this kind more convenient 

 than a coal-flre. 



On the side opposite to that by wliich the foul air is carried off, a num- 

 ber of ventilators should be put in place of the upper panes of the win- 

 dows, and arranged so as to be opened more or less as needed, in order 

 to admit the fresh air as near as possible to the ceiling. By increasing 

 and suitably arranging these openings, the injurious effects from the 

 entrance of cold air will be avoided. 



Arrangements of this kind have been recently adopted in the school 

 at Saint Martin's Market, kept by the Christian Brothers, where there 

 are about 100 scholars in the drawing-room every evening, light being 

 furnished by a great many gas-burners. Simple wooden pipes carried 

 up to the roof, and the employment of a few gas-burners, prove suffi- 

 cient to carry off' the foul air and gas, and indirectly to draw in fresh air 



