Show Pure Air Devices In Demand Hard apace after the water filter and distiller In tho race for hygiene comes the ventilator A Boston builder build-er says that ventilation Is In effect the process of dilution and that when the vitiation to bo maintained In apartments Is decided the necessary constant supply of fresh air to maintain main-tain this standard may be calculated Tho average production of carbonic acid by an adult at rest Is 06 cubic feet per hour tho proportion of this gas in the external air being four parts in 10000 The 06 cubic feet of carbonic add produced per hour by a single Individual will require for Its diluting 3000 cubic feet of air per hour But the absolute air volume to be supplied cannot be specified with thorough knowledge of all the outa conditions and modifying clrcum stnnccsthe climate construction of tho building size of tho rooms number num-ber at occupants their healthfulness and activity together with the time occupied all must be considered |