APPENDIX No. 2. REPORT OF SUPERINTENDENT OF NAVAL OBSERVATORY. BUREAU OF NAVIGATION, Washington, D. C., November 12, 1913. From: Superintendent, Naval Observatory. Subject: Report of the Superintendent, Naval Observatory, for the fiscal year ending June 30, 1913. The United States Government was represented at the International Time Conference which was held in Paris in October, 1912, by the naval attaché at Paris, Commander H. H. Hough, United States Navy, and Prof. A. Hall, United States Navy, of the Naval Observatory staff. This observatory, being the first institution in the world to have its time signals regularly transmitted by radiotelegraphy, was naturally deeply interested in an international conference which was largely devoted to questions concerning the distribution of time by this means, especially as preparations were in progress to use the Arlington radio station to send out time signals of great radius. Our delegates were therefore instructed in part as follows: The department desires you to inform the conference that it has been sending out radio time signals regularly since January, 1905, and that the practice will be continued from the Arlington station with the idea of reaching ships as far at sea as possible; but it desires to do this so as not to interfere in any way with the signals from the Eiffel Tower. On the contrary it desires to cooperate with the work of that station so far as it may be mutually advantageous. It may be necessary to send a night signal from the Arlington station in addition to the one at noon in order to reach the maximum distance. This signal should be sent as soon after darkness has covered the North Atlantic Ocean, Gulf of Mexico, and Caribbean Sea, as suitable for the purpose, and so as not to interfere with any wellestablished radio business. The best time for this signal might well be a subject of consideration by the conference, so as not to conflict with any other undertakings to be considered by it, as well as the question of a standard of time to be used for all such undertakings. A program of time signals for cooperating stations to avoid conflict among them and with commercial stations would be desirable. The conference may be informed that the department is disposed to favorably consider the use of the Arlington station for the exchange of messages relating to important astronomical discoveries, such as new asteroids, or hydrographic and meteorological information. Commander Hough was appointed the delegate to represent the United States at the conference which met in Paris October 20, 1913, with powers to sign a convention based on the one submitted by the French Government as a result of the labors of the conference of October, 1912, but somewhat modified, subject, however, to the approval 22914°-NAVY 1913-10 145 of the Senate and such legislative action as may be required to give the instrument effect and with the following reservations: First. That the United States may send time signals from such radio stations of its own as it may designate and at such time as it may decide upon. Second. That it may be free to use, in sending radio time signals, the method that it has used in the past, or such modification thereof as may seem to it desirable. Third. That it is to be understood that in agreeing to this convention, the United States Government does not undertake to exercise any control over private radio stations that may possibly be contemplated beyond what is permissible under existing laws. It is not considered desirable for the department to agree to limit the number of its stations to send radio time signals to the three named in the journal of the conference. New stations are to be built at Panama Canal Zone, Hawaii, etc., and it is probable that it will be desirable to send such signals from some or all of these. It is believed, however, that it can regulate the signals so as to help rather than interfere with international interests. About the time that the invitation to attend the Paris conference was received, the superintendent was interested in the problem of determining "lag," or the amount of time lost in transmitting signals to the radio stations and automatically converting them into radio signals. Three methods suggested themselves as possible: First, for a near-by station such as Arlington, the chronograph, using a coherer or other wave detector permitting the use of a recording device, but this involved a determination of the time taken to operate the detector and recorder or the elimination of this time as a factor; second, some chemical recording device in which the passage of the Hertzian wave would produce a change in color or a reaction which could be made visible as in the photographic process; and lastly, the application of the well-known coincidence method for comparing time pieces keeping different times. With these ideas in mind, steps were taken to install at the observatory, radio-receiving apparatus for the purpose of experimentation. Soon, however, attention was called to an article in Revue générale des Sciences pures et appliquées, entitled Emploie de la Télégraphie sans fil pour la Détermination des Longitudes by Claude, Ferrié, and Driencourt. Here was a beautiful method of eliminating "lag" by the method of coincidences already worked out and utilized in the transmission of signals for the determination of differences of longitude. The radio-receiving apparatus was installed notwithstanding this fact, and has proven very useful, but the development of the new longitude method opened the way to a very important undertaking. The Hydrographic Office had already used the observatory time signals, which were transmitted to Key West by land lines and there automatically converted into radio signals, for longitude determinations, but it seemed desirable to lose no time to familiarize ourselves with the new method. The longitude of the Naval Observatory referred to Greenwich or Paris had never been determined directly, but was based on determinations of the longitude of Cambridge, Mass., and Montreal. A letter was, therefore, written to the Navy Department recommending that its representative at the International Time Conference be directed to take up with the authorities of the Observatory of Paris the question of the arrangements necessary for the determination of the difference of longitude between the observatories of Paris and Washington, using the radio stations at the Eiffel Tower and Arlington for transmission of signals. This recommendation was approved and Commander Hough was instructed accordingly. Besides taking the matter up with the French authorities he read a translation of the letter to the conference, which received it favorably, but took no formal action in regard to it, as none was necessary. The French scientists have taken great interest in the problem and in March last sent five of their leading experts to this country to study it and make preliminary tests. These gentlemen were Hydrographic Engineer in Chief L. Driencourt, French Navy; Commandant G. Ferrié, French Army; Capt. Levesque, French Army; Lieut. C. Gignon, French Navy; and Prof. H. Åbraham, of the faculty of sciences of the University of Paris. At the same time we had in Paris Commander Hough and Prof. Hall representing this country. The Frenchmen brought with them a prismatic astrolabe and used it for taking astronomical observations. Time signals were exchanged and the results were such as to make very certain that the work of this fall and winter will be successful. Prof. Abraham was detailed by the minister of public instruction and brought over his apparatus for recording signals photographically to test its applicability to the problem. The astrolabe was left at this observatory for trial and is now being used by Assistant David Rines. Messieurs Claude and Driencourt have devoted much study to this instrument and have written a valuable treatise describing it and its use. Much time has been spent in making preparations for the work which began in October. Two transit instruments were ordered of G. Prin, of Paris, to conform to the following specifications: Aperture, 3inches; focal length, 33 inches. Self-registering right ascension micrometer, driven by electric motor, and controlled by hand. Arrangement for reversal on each star. Pivots of hardened steel. Electric lighting. Meridian mark, and long focus lens. Two specially designed instrument houses have been built, side by side, in the observatory grounds. Three pairs of wires have been made available for transmitting signals between the observatory and the radio station at Arlington. While it is expected that the American and French parties will work simultaneously their astronomical methods and some other details may differ. The American party now in Paris consists of Assistant Astronomer G. A. Hill, Lieuts. R. B. Coffman and C. W. Magruder, and Ensign G. S. Gillespie. Mr. Hill and Mr. Magruder are detailed for astronomical work and the other two for coincidence work. This party is placed under the supervision of Commander Hough, who has been of great assistance in making arrangements in Paris. The party working here is composed of Prof. F. B. Littell, Lieut. W. T. Mallison, and Ensigns H. E. Saunders and R. A. Lavender. The first two are detailed for astronomical work and the others for coincidences. The parties will change stations after a sufficient number of observations have been taken, and signals exchanged, each carrying its transit instrument with it. There have been a great many details to work out in connection with this undertaking and the distance separating the two observa tories has made cooperation between them difficult. Much credit is due the officers for the enthusiastic manner in which they have undertaken the work. Owing to the great range of the signals that are to be sent out from Arlington in connection with this work and length of time over which they are to be spread it was seen that other institutions might take advantage of them to determine their longitude. Accordingly a circular letter was issued giving information concerning the signals and a number of replies indicate that the opportunity will be embraced by institutions widely scattered, one being as far west as the University of California. It is also contemplated establishing the longitude of a point in Haiti in connection with the survey on which the U. S. S. Eagle will be employed, and one or more in Central America in connection with the survey on which the U. S. S. Hannibal will be employed. After the time conference adjourned Prof. Hall visited under orders the following observatories and institutions doing work along lines in which this observatory is specially interested and submitted a report for its use: France: Observatoire de Paris, Paris. Observatoire d'Astronomie Physique, Mendon, Paris. Bureau International des Poids et Mesures, Sèvres, Paris. Service Géographique de l'Armée, Paris. Observatoire du Bureau des Longitudes, Montsouris. Paris. Germany: Astronomische Sternwarte und Astrophysikalisches Observatorium, Königstuhl, Heidelberg. Königliche Sternwarte, Bonn. Königliche Sternwarte, Berlin. Königliches Astronomisches Recheninstitut, Dahlen, Berlin. Königliches Geodätisches Institut, Potsdam. Königliche Sternwarte, Kiel. Hamburger Sternwarte, Bergedorf. Deutsche Seewarte, Hamburg. England: Royal Observatory, Greenwich. Kew Observatory, Richmond, Surrey. National Physical Laboratory, Teddington. Hydrographic Department of the Admiralty, London During the fiscal year and subsequently the superintendent has been favored with the privilege of visiting and conferring with the directors of the following observatories: Harvard College, Yale University, Dudley, Columbia University, Flower Astronomical, Dearborn, Yerkes, Washburn, and Smith. It has been his desire to extend this list, but time has not permitted. During the year there has been put in effect a plan of bringing together those who are interested in the science of astronomy and related subjects to discuss developments in those lines and with the object of increasing the interest of the personnel of the observatory and stimulating them to their best efforts. From October to May, both inclusive, meetings are held twice a month from 3.30 to 4.30 p. mn. A number of very interesting and instructive papers have been presented, and much interest has been aroused in the meetings. The |