310 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 11, NO. 13 



controlled relay energizes one of the pen magnet coils during the brief 

 period of the clock break. If the pen is in the released position dur- 

 ing the clock break the pen magnet is momentarily magnetized and 

 the pen is momentarily moved against the inner stop. If the pen is 

 in the attracted position the clock break will serve to demagnetize the 

 pen magnet momentarily and the pen will be released against the outer 

 stop during the break. The pen will record the clock break, there- 

 fore, no matter what its status with reference to the radio signal. 



When star transits are to be recorded simultaneously with a local 

 chronometer, the pen magnet winding previously utilized for the re- 

 cording of the radio signals may be included in a local signaling cir- 

 cuit. The tapping of the signal key then operates in a manner sim- 

 ilar to the starting of a radio signal. 



Oscillographic study of the performance of a regenerative circuit 

 with a telegraph relay with double contact in the plate arm and with 

 the screening coil for stopping the regeneration, has shown that the 

 oscillations are started and stopped well within 0.001 second. Figure 

 5 shows clearly that on the one hand we have a chain consisting of 

 antenna — relay — pen circuit — pen, and on the other, chronometer — 

 relay — pen circuit — pen. The two relays are similar and their re- 

 action times are less than 0.001 second. Their difference will be 

 considerably smaller than this amount. The pen circuits are also sim- 

 ilar, and finally the pen is identical. 



It is seen clearly that the system has been designed to minimize the 

 lag difference of the two kinds of signals. Since comparisons of two 

 different kinds of signals are to be made, it is only the consistency and 

 magnitude of the lag difference which is of importance. Measure- 

 ments of this quantity are to be made in a number of receiving-record- 

 ing sets prior to their use in the field. The U. S. Coast and Geodetic 

 Survey proposes to obtain an additional check by occupying a sta- 

 tion of precisely known longitude and working the problem back- 

 wards. Thus the lag will be subjected to independent measurement 

 in the laboratory and in the field. It is confidently expected that by 

 the use of this recorder a new order of precision will be attained in 

 measurements of the kind in which this apparatus may be employed. 



BIBLIOGRAPHY 

 Simon, Hans. Jahrb. drahtl. Telegr. 2: 409-416. 1908-09. 

 TuRPAiN. A. Rev. Electrique. 18: 211-214. Sept. 1912. 

 TuRPAiN, A. Bull. Soc. Int. des Electr. (3) 3: 299-322. 1913. 

 Abraham, H. Bull. Soc. Int. des Electr. (3) 3: 649-662. July 1913. 

 CampbELL-Swinton, a. a. Proc. Wireless Soc. London, 1914. 



