The Subway and Mr. Tesla

Statement by the Electrical Director of the Interborough Company.

TO THE EDITOR OF THE SUN — Sir: In a letter printed in your issue of June 16, Mr. Nikola Tesla points out what he says he considers a source of danger in the subway, and reiterates an opinion, which he has previously expressed in your columns, to the effect that a mistake was made in not adopting what he calls “my alternating system of distribution, popularly known as the ‘two,’ ‘three,’ multi, or polyphase.” It is possible that some of your readers who have read none of Mr. Tesla’s prophetic essays which have appeared from time to time during the last ten or fifteen years in the daily press may attach weight to his opinions, and as the public is greatly interested in the subway and its operation, statement of a few facts seems pertinent and proper.

It will be recalled, perhaps, by your readers that in your issue of Nov. 1, 1904, a letter from Mr. Tesla was published, in which, inter alia, he expressed the opinion that polyphase induction motors should have been adopted instead of continuous current motors. Incidentally, he remarked also that the distributing mains ought to be insulated artificially by refrigeration, that he had recently perfected inventions which, “abolishing all barriers to electrical development, will soon sweep the world with irresistible force,” that he approved Mr. Belmont’s private car, that he had not seen the tunnel and did not know its location; and was equally ignorant as regards the power house, that the system adopted was of his own invention, but that it represented “the state of the art more than ten years ago”; that a mistake had been made in not asking the electric companies to furnish the best instead of the cheapest equipment, and that the Interborough Rapid Transit Company had never asked him for any expert advice or suggestion.

In a letter which was printed in your issue of Nov. 11, 1904, I stated that Mr. Belmont and his associate directors had imposed upon their engineering advisers no limit of cost; that if any mistake in the selection of electric equipment had been made, it was mine — not Mr. Belmont’s — and suggested that, if Mr. Tesla would present before the American Institute of Electrical Engineers a paper containing specific and definite criticism of the equipment, I should be glad to meet him for the purpose of a full and frank discussion.

This suggestion, for reasons which were perhaps satisfactory to himself, Mr. Tesla declined to adopt, and in a long letter, which you printed in your issue of Nov. 27, 1904, in declining to appear before the institute, he referred to a number of alleged accidents in the subway — the majority of which never happened — and again stated that the system adopted was one which he had “devised many years ago”; that its adoption in this instance was altogether too absurd to dignify it with any serious comment; that polyphase induction motors should have been used, and that he believed in advertising.

In his latest letter, that of June 16, he reiterates some of the statements contained in previous letters, and calls attention in the following words to a new danger which he has discovered: “The danger to which I refer lies in the possibility of generating an explosive mixture by electrolytic decomposition and thermic dissociation of water through the direct currents used in the operation of the cars.” His alternating current polyphase system, as he says, would be free from this danger. Obviously, a charge so serious as this should rest upon a very substantial foundation of fact, and no consideration of self-interest or of personal animosity will excuse its author unless he can prove his charge. And what does Mr. Tesla offer as evidence that electrolytic decomposition of water is taking place in the subway? He says: “It will be recalled that an expert found the percentage of free oxygen in the subway appreciably above that which might reasonably have been expected in such a more or less stagnated channel.” In other words, the subway air contains more oxygen than Mr. Tesla expected, and upon this fact he constructs his theory of the production of oxygen and hydrogen gas by electrolysis. He does not offer in his letter a scintilla of evidence that oxygen is thus being set free. No one has alleged that the air in the subway contains more oxygen than uncontaminated free air. If Mr. Tesla, therefore, is comparing an actual analysis with anything more definite than his own notion of the kind of air that might be expected in the subway, it is for him to make clear his reasoning.

Prof. Charles F. Chandler, who was recently employed by the Health Department of the city of New York to test the condition of the subway from a sanitary standpoint, with especial reference to the purity of the air, says:

According to the best authorities, as, for example, Dr. John S. Billings, in his work “Ventilation and Heating,” the chemical composition of the atmosphere when uncontaminated is as follows:

Oxygen.........................................................................20.80
Nitrogen........................................................................79.20
Carbon dioxide.............................................................0.03 or 0.04

The composition is not absolutely constant, the oxygen being sometimes a little higher and sometimes a little lower than the percentage given above.

Thus far fifty samples of subway air have been carefully analyzed and the percentage of oxygen determined, the result being a maximum of 20.80 and a minimum of 20.30 — average 20.55. At the same time, nine samples of surface air were examined, showing a maximum of 20.90 and a minimum of 20.00 — average 20.76.

It will be noted that the percentage of oxygen in subway air, as determined by Dr. Chandler, is a little less than that of normal uncontaminated air; there is therefore no excess of oxygen to be accounted for.

Among all that Mr. Tesla has said upon the subject, three charges besides that relating to alleged excess of oxygen perhaps call for reply in order that any part of the public which may have been disturbed by his statements may be reassured. These charges are: (1) That a mistake was made in not adopting polyphase induction motors; (2) that “not a single electrician of the General Electric or Westinghouse companies was consulted,” and (3) that “a mistake was made in not asking the electric companies to furnish the best instead of the cheapest equipment.”

The last of these charges I answered in my letter of Nov. 11, 1904. It is absolutely without the slightest foundation in fact. The management of the company aimed to secure the best system available, and no limitation in respect to cost was imposed upon its engineers. Apparently Mr. Tesla seeks to convey the impression that the polyphase induction motor system is more expensive than that adopted. As a matter of fact, the reverse is the case, the chief claim of the induction system residing in the fact that it is less expensive than the system which the Interborough company has adopted. Several years ago, when tenders were submitted by manufacturers to the Metropolitan and District Underground Railways in London, the induction motor system was proposed by Ganz & Co. of Budapest, and the price asked was approximately two-thirds the average price of the competing tenders, which were based upon the system which has since been adopted for the New York subway.

The responsibility for decision in respect to the system adopted rests primarily upon me, but the plans were duly examined and approved by Messrs. Duncan and Hutchinson, Consulting Electrical Engineers to the Rapid Transit Commission. As regards consultation with electricians and engineers of the General Electric and Westinghouse companies, I have been in touch with the leading representatives of both companies from the outstart of this work up to the present time. Many of these gentlemen have contributed largely to the success of the installation and operation of the electrical equipment, and, so far as I am aware, are unanimous in believing that the best system available was adopted.

In support of his contention that a mistake was made in adopting the system which is in use, Mr. Tesla has offered simply an expression of his personal opinion. The polyphase motor system, as developed by Ganz & Co. of Budapest, undoubtedly has very strong points to commend it under certain conditions; and for what Mr. Tesla did in the early days of its inception the engineering world is under obligation, which in America has been fully recognized. Since certain United States patents were issued to him in 1888, however, he has done little, if anything, toward perfecting the motors, and still less toward the development of the multitude of other devices which in the aggregate constitute an electric traction system. Scott, Lamme, Steinmetz, Berg and others in Pittsburg and Schenectady have developed and improved the induction motor so that it is now extensively used in stationary work; but it has never been used in America for traction purposes upon any scale which would have justified its adoption by the Interborough company. In Europe, within the last five or six years, the engineers of Ganz & Co. have developed it for traction purposes, and under certain conditions they have demonstrated its value in this field. Possibly this fact explains Mr. Tesla’s recently revived interest in the motor of this type.

In conclusion, I may mention the fact that the system adopted for the operation of the subway and elevated is identical with that adopted in Paris for the operation of the Metropolitan, in London for the operation of the so-called “Twopenny Tube,” the Metropolitan and the District railways; in Brooklyn for the operation of the elevated lines; that it has been adopted by the engineers of the Pennsylvania Railroad, the Long Island Railroad and the New York Central and Hudson River Railroad, and is largely used throughout America for the operation of interurban railways. The induction motor system, as supplied in Europe by Messrs. Ganz & Co., is beyond question an operative and in many respects most excellent system. Hitherto, however, American manufacturers have not placed such a system upon the market. I think I am safe in saying that at the time when Mr. Tesla thinks the induction motor should have been adopted in the subway not a single motor of this type was in use in ...