The New York Rapid-transit Subway
Forfatter: Willialm Barclay Parsons
År: 1908
Forlag: The Institution
Sted: London
Sider: 135
UDK: 624.19
With An Abstract Of The Discussion Upon The Paper.
By Permission of the Council. Excerpt Minutes of Proceedings of The Institute of Civil Engineers. Vol. clxxiii. Session 1907-1908. Part iii
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Proceedings.] CORRESPONDENCE ON NEW YORK SUBWAY.
127
subway as compared with 6,500 bacteria per cubic metre of air in Dr. Soper,
the street. Some results of bacterial analyses by the familiar plate
method were given in Fig. 28. The impurity which was most
Figs. 27.
Hourly Variations in the Amount of CARBON Dioxide in the Air of the
Subway. (Average of 1,244 Analyses.)
suggestive of danger to health was iron-dust. This dust was
produced by the wear and tear of metallic surfaces, especially brake-
shoes. The consumption of brake-shoes alone amounted to about
Average Numbers of Bacteria which Subsided from the Air per Square
Foot per Minute in the Subway and Streets, 10 July-2 October,
1905. (Samples Fepresented, 2,742.)
1 ton for each mile of road per month. There was no difficulty in
finding the metallic particles in the air or in the dust of the subway.
He had found metallic dust of similar character in all the subways