The New York Rapid-transit Subway

Proceedings.] CORRESPONDENCE ON NEW YORK SUBWAY. 129 the action of the trains upon the atmosphere moving freely through Dr. Soper, large openings to the outside air. It had been found that for a given volume of air-space in any section of the subway a certain area of opening was necessary and sufficient for good ventilation (Fig. 29). The secret of ventilating a subway of this type lay, in his opinion, in arranging openings to the outside air so that they should be of proper area and location. Experience with the New York subway had shown that, beside the amount of ventilation which could take place in this way, the exchange of air which could be produced under practical conditions by means of mechanically propelled blowing-devices was immaterial. At first the principal air-openings in the New York subway were at the stairways at the Fig. 29. BROOKLYN BRIDGE WORTH ST CANAL „ SPRING ., BLEECKER ST ASTOR PL 14-TH ST 18TH >. 23«P „ 28™. 3380 GRAND CENTRAL TIMES SQUARE _____= RATIO OF EFFECTIVE AREA OF _________= DIFFERENCE BETWEEN AMOUNT OPENINGS TO CUBIC CONTENTS_________________OF CARBON DIOXIDE INSIDE OF AIR-SPACE. AND OUTSIDE OF SUBWAY. Relation Between the CHEMICAL Condition of the AIR in the Subway and the Ratio of the Effective AREA of the Openings to the Cubic Contents of the Air-Space at DIFFERENT Stations. stations, although there were some blow-holes in a part of the line above 59th Street. Later, many more blow-holes were opened through the roof. He had no knowledge of the need or efficiency of the automatic air-valves, electric fans, and cooling-apparatus which had been installed since the conclusion of his investigations. As nearly as could be judged without information as to the number of passengers carried at different times and in different parts of the subway, the analyses indicated that an amount of air entered and left the subway equivalent to a renewal of the whole atmosphere at least every 3 hour. This was before any material changes were made in the original method of ventilation. Mr. Parsons’s [the INST. C.E. VOL. CLXXIII.] K