The New York Rapid-transit Subway

a roceedings.]‘ DISCUSSION ON NEW YORK SUBWAY. 123 the best bond, should not be painted. The members asking for The Author, information in regard to the conditions of the air in the Subway were referred to a communication by Dr. George A. Soper (below), who had been specially retained by the Transit Commission to report on such matters. It should be remembered that not only were there many more trains in the New York subway than in any similar railway, but these trains generated more power, namely, 2,000 HP. on each express and 1,200 HP. on each local train. Nearly all this energy was dissipated as heat. In conclusion, the Author desired to express his appreciation of the reception of the Paper by the members of The Institution, and of their references to the work it described. Naturally much had been said in the discussion in comparison with tubes, and as to the possibility of shallow construction in London, on which opinion seemed to be divided. He had presented the Paper in order to record a work executed under conditions differing in many respects from those existing in London. The difficulties peculiar to London were many and great. Whether they could be overcome, and, if overcome, whether a shallow subway would be profitable, as had been accomplished on a large scale in New York, Boston, Berlin and Paris, was not for the Author to discuss within the limits of the Paper, Correspondence. Dr. George A. Soper, of New York, communicated the following Dr. Soper, observations upon the ventilation of the subway :—Shortly after the subway was opened, reports appeared in the Press to the effect that the ventilation was defective. These reports were made by volunteer investigators who claimed to have analysed the air and found it to be alarmingly impure. Upon inquiry, these investigators turned out to be unreliable persons and their results untrustwortliy. But harm had been done, and a considerable number of people had come to regard the air witli suspicion. In the hope of establishing the truth about the air, Professor Charles F. Chandler, of Columbia University, made a number of accurate analyses. He pronounced the air good. This allayed suspicion for a time, but soon the heat, which became noticeable about 5 months after the line was put in service, revived the belief that the air was vitiated. At this point Dr. Soper was