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Scientific Proceedings (65). 



and ten feet high and is insulated with two inches of cork board 

 and a half inch coating of cement with a smooth white cement 

 finish. A skylight at the top is fitted with three sashes and the 

 room is entered through three doors with air chambers between. 

 The subjects may be observed from the apparatus room through a 

 window. Air may be supplied to the observation room through 

 one or more of four 12-inch openings in a 12 x 18 inch vertical duct 

 and may be exhausted from a similar duct at the other end of the 

 same side of the room. The air flow is measured at the inlet by a 

 meter specially designed for the purpose. For maintaining desired 

 temperature and humidity conditions without fresh air supply, the 

 observation room is equipped with ammonia cooling coils, steam 

 radiators and a humidifying pan. Desk fans are provided for 

 securing local air circulation. Continuous records of temperature 

 and humidity in the observation room are made by means of a 

 Bristol recording psychrometer and samples of air for carbon 

 dioxide determinations are collected by continuous aspiration 

 through a wash bottle of sulphuric acid. 



The apparatus room (11H x l 4 iee t by 11 feet high) contains 

 two 8x9 inch multivane fans for supply and exhaust and insulated 

 ducts by means of which air is drawn in from above the roof and 

 delivered either to the observation room or the apparatus room 

 itself. Air may also be recirculated continuously through the 

 observation room. The volume of air may be varied between 30 

 and 350 cubic feet per minute. The main duct is provided with 

 tempering and reheating coils, and with a Warren Webster air 

 washer for humidification and a drying tank containing trays of 

 calcium chloride. The apparatus is fitted at all essential points 

 with automatic apparatus for temperature and humidity control. 

 It has, however, always been found necessary to supplement the 

 automatic regulation by manual control. The apparatus room 

 also contains animal cages surrounded by revolving glass boxes for 

 exposing animals to the effect of dust-laden air. 



The ammonia coils in the observation room are served by a 

 four ton Brunswick Refrigerating Co. compressor with appurte- 

 nances. 



The plant was designed to maintain conditions varying from 

 those existing out of doors or less up to ioo° F. in zero weather, with 



