314 



WARMING AND VENTILATION. 



ter, and terminate in the movable copper water-basin =5, which form 

 siphon'traps and prevent the rising of the gas. from the well. 

 FIG.3I. 



All the ventilating-pipes from the seats 

 are 4 inches by IC inches inside. They ter- 

 minate in a large vertical collecting-pipe, 

 about 10 square feet in sectional area, serv- 

 ing as a ventilatiug-chimney, in which are 

 placed vertical hot-water pipes, which in 

 winter produce a general draught. In sum- 

 mer, when the heating is interrupted, the 

 draught is produced by gas-burners kept 

 burning in each closet. 



Veutilation by means of hot- water circu- 

 lation can evidently be kept up in summer 

 by means of a separate fire for this special 



purpose, which would be more economical than the use of gas. 



The result of experiments made in February, 18G3, was that the 

 amount of air removed for each seat under the action of the draught, pro- 

 duced simply by an excess of 7° to 13^ of temperature in the chimney 

 over that of the external air, was more than 2,200 cubic feet an hour. 



Although much greater than is generally necessary, this amount would 

 not seem excessive in similar cases where, in addition to the seats, uri- 

 nals, often imperfectly rinsed, are used. 



111. Arrangement adopted at Lariboislere Hospital, {Fig. 32.) — In this 

 establishment, the closets on each floor contain three seats, with bowls, 



