304 WARMING AND VENTILATION. 



closed at will by means of internal valves furnished vfitli self-closing 

 springs. 



As the air thus introduced may be too cool at night, it is necessary 

 that it should be directed from the lower part of the room toward the 

 ceiling, and that its velocity at entrance should be about 2 feet a second, 

 in order that it may be rapidly diminisbed before it arrives at the 

 escape-openings. 



The regulating-apparatus connected with the registers should be so 

 arranged as to be exclusively under the control of those in charge of 

 this service. 



When any arrangement for ventilation on the exhaust-system has 

 been carried out, it may easily be determined by direct experiments 

 easily made in the main ventilatiugchimney, or, if desired, in the sepa- 

 rate flues, whether the jirescribed amount of air is really drawn off, 

 and what is the corresponding excess of temperature in the chimney 

 over that of the external air; and If with this excess, which usually 

 will not vary, as has been previously stated, much from 35° to 45°, the 

 ventilation be found sufficient, it will then only be necessary to regulate 

 the heat in the chimney so that its temperature will always exceed by 

 the same amount that of the external air. 



92. Arrangements for ventilation in summer. — When the main halls of 

 the hospital are warmed at the same time by general heaters and by 

 fire-places — of which latter the ventilating fire-places described in § 13 

 should be preferred, as they at the same time carry off foul air and 

 introduce a considerable amount of fresh air properly warmed — open- 

 ings for the admission of fresh air should be made in addition to those 

 of the ventilating-chimney, and arranged, as has been described, for 

 summer-ventilation. 



Stairways, waiting-rooms, and other places giving access to the halls 

 should be heated to a temperature which, especially for the latter, 

 should be at least equal to that of the halls. In this way, their effect in 

 producing draughts of air will be diminished. It would be well, then, 

 to put up heaters in these places even when fire-places are used in the 

 main rooms, 



93. Use of tJie heat given out hy the lights. — In hospitals lighted by gas, 

 it will be well to assist the draught by means of the heat given out by 

 the burners, which plan will have the double advantage of rendering the 

 ventilation more energetic, and of removing the unhealthful products 

 of combustion. This should especially be applied in the case of water- 

 closets, which should have double doors opening from without inward 

 in the direction of the draught. 



The kitchens and the imvies of hospitals should be removed from the 

 hospital proper, and ventilated by a powerful current similar to those 

 which will be described hereafter for such places. 



94. Dispositio7is to he made in case of crowding or epidemics. — When the 

 draught is produced by a circulation of warm water or steam, the energy 



