292 BIOLOGICAL PROBLEMS 



4. A window (or windows) must be opened day and 

 night in every occupied room. If weather conditions 

 limit the application of this rule, the door should be 

 kept wide open. The fireplace and chimney opening 

 must never be blocked. 



5. To aid the toleration of cold fresh air (and in 

 windy and wet weather) certain simple contrivances 

 are useful. It is important that cold fresh air should 

 enter a room in an upward direction, at a height which 

 is above the heads of the seated occupants; it then in 

 rising loses its initial velocity and falls as a gentle air 

 cascade over our bodies. Hinckes-Bird's well-known 

 device is to place a solid block of wood or glass under 

 the entire length of the lower-sash frame of a window, 

 which has the effect of raising the top rail of the lower 

 sash above the bottom rail of the upper sash ; and so, 

 while excluding wind, rain, and snow, air is admitted 

 between the two overlapping sashes in an upward 

 direction. Or Venetian blinds, with the laths turned 

 upwards, may be fixed over a partly open window. 

 Or wire gauze on a frame is made to fit accurately an 

 opening left by lowering the upper sash. Of course 

 a hopper inlet window with side checks is far more 

 efficient than the foregoing contrivances, and these 

 should be general in all of the larger offices and work- 

 rooms. Valvular openings into the chimney flue near 

 to the ceiling (Arnott) constitute a simple and cheap 

 provision, when a fire is burning, that usefully aids air 

 renewal in fully occupied sitting-rooms. 



6. Beds and chairs should not be placed in the line 

 of main draughts as between the windows and fire, 

 or between windows and doors of rooms; or when it 

 is difficult to avoid the direction of draughts, a screen 

 may be used to shield the body. Such screens may 

 be easily improvised. 



7. The body must be warmly clad with light woollen 



