March 13, 1913] 



NATURE 



the divisions in seconds on the outer circle, the 

 system can be easily understood. 



It will thus be seen that each short signal or 

 tap will give the receiver a chance of comparing 

 his clock, and the dissimilar preliminary signals 

 will inform him whether the minute involved is 

 the 58th or 59th. 



When all stations brinp- this excellent and very 

 simple system into operation, it will be most easy 

 for anyone unacquainted even with the Morse 

 alphabet to check their clocks correctly. 



Xow while the above arrangements as regards 

 the distribution of time will come into force on 

 July 1 next, the questions as regards the type of 

 weather messages, which will be transmitted 

 directly after the time 

 signals have been sent 

 out, are not yet settled. 



There is little doubt, 

 however, that each trans- 

 mitting station will send 

 out a general description 

 of the air movements 

 over a wide area of 

 which the station is about 

 a centre, and also some 

 definite data as regards 

 certain specified stations 

 useful for that area. 



At the present time 

 both Paris and Norddeich 

 send out such messages, 

 and it may be of interest 

 to describe the proce- 

 dure now followed at the 

 former station, for it 

 is probable that little, 

 if any, change will be 

 made with regard to 

 the system there in 

 vogue. 



Let us suppose that 

 the time signals at 

 ioh. 45m. os., ioh. 47m. 

 os., and ioh. 49m. os. 

 have just been trans- 

 mitted from the Eiffel 

 Tower, then there follow 

 immediately after them 

 the weather signals. It 

 may be mentioned again 



that the signals are sent through quite slowly, 

 so that with a little practice they can be easily 

 recorded and deciphered. 



A typical message received in London on 

 January 28, 1913, ran as follows : 



[a) -=ECM = R.5iooo=\'.49i424 = 0.551633 = 



C.62 1 8 1 2 = H. 653043 = S.46207 = 

 Pression basse ouest Europe elevee nord= = 



(b) R.";]ooo = V.49i424 = 0. 551633 = 

 0.621812 = 11.653043 = 8.46207 = 

 Pression basse ouest Europe elevee nord = 



V) Paris = vent 9 metres stationnaire sud croit pression 

 75S stationnaire ciel couvert= = 



J 1 V. 9 m ss sud cc pp 758 ss ciel convert 



NO. 2263, VOL. 91] 



Then follow the signals : 

 ._._. (end of transmission'. 



(FL repeated several times, which 



denote Eiffel Tower). 

 And lastly 

 ...-._ (end of work). 



The above message has been divided into four 

 sections and marked (a) (b) (c) (d), in order to 

 show that (b) is simply a repetition of (a), and that 

 (d) is a repetition of (c), only sent in brief, i.e. 

 "V" corresponds to "vent," "m" to "metres," 

 "ss " to "stationnaire," &c. 



In deciphering the message only (a) has to be 

 considered, because (c) explains itself, being the 



:. — Diagram to illustrate tb 



July, 



general weather conditions at Paris stating the 

 velocity of the wind in metres per second, direc- 

 tion of wind, pressure in millimetres, and state of 

 sky. At 3 p.m. each afternoon a similar message 

 stating the meteorological conditions at Paris is 

 transmitted from the Eiffel Tower. 



With reference to (a), then, the message con- 

 tains information relating to (1) atmospheric pres- 

 sure, (2) wind direction and force. (3) the state 

 of the sea, in code from the following six stations : 

 Reykjavik (R), Valencia (V), Ushant (Ouessant) 

 (O), Corunna (C), Horta (H) (Azores), for 

 7 a.m. ; and for St. Pierre (S) (Miquelon, New- 

 foundland) for the preceding 8 a.m. (see Fig. 2). 



