254 KADIOTELEGRAPHIC INVESTIGATION. 



These points have previously been investigated to only a slight 

 extent. The observers of signals during the solar eclipse of the 

 17th April, 1912, nearly all agreed that the strength of the signals 

 was greater during the eclipse than an hour before or after. 

 There was only one special observation of strays during the same 

 eclipse, when very pronounced and remarkable variations were 

 recorded during the passage of the shadow-cone across Europe. 

 To investigate the propagation of signals across the umbra it will 

 be necessary to arrange for wireless telegraph stations on either 

 side of the central line of the eclipse to transmit signals at intervals 

 while the umbra passes between them. This transit of the 

 umbra occupies about two minutes. It is thus very desirable that 

 the Scandinavian and Russian stations should transmit frequently 

 throughout several minutes before, during, and after totality. But 

 stations other than those favoured by their proximity to the central 

 line should endeavour to keep a complete record of the variations 

 of signals during the eclipse. Stations in Europe west of the cen- 

 tral line and stations in the Mediterranean and in Asia Minor 

 may find noticeable changes in the strength of signals, particularly 

 long distance signals, l^etwcen the hours of 10 a.m. and 3 p.m., 

 Greenwich time ; and it is probable that the stations of India and 

 East Africa, and ships in the Indian Ocean, may feel the efifect of 

 the penumbra in the afternoon. On the other hand, ships in the 

 Atlantic, and fixed stations in Eastern Canada and the United 

 States, will probably be affected by the penumbra in the early 

 morning. At Montreal the eclipse (partial) is at its greatest 

 phase at 5.52 a.m. Standard Time. It is possible that the eclipse 

 may have some influence even when it is invisible. The investiga- 

 tion of strays is of as great interest as that of signals. So far as 

 is yet known, the natural electric wa\es reaching wireless tele- 

 graph stations in latitudes higher than 50° appear to travel mostly 

 from the south. Thus the greatest changes produced in strays by 

 the eclipse will probably Ije experienced at stations in Scandinavia 

 and Russia, to reach which the waves must cross the path of the 

 umbra. At the same time changes of some kind are to be expected 

 in other districts than these, and it is therefore desirable that statis- 

 tical observations of natural electric waves be made all over the 

 world, and especially at places within an earth quadrant of South- 

 ern Russia. It is also desirable that meteorological observations, 

 including those of atmospheric ionisation and potential gradient, 

 should be at the disposal of the Committee when considering the 

 records of strays and signals. The Committee proposes to prepare 

 and circulate special forms for the collection of statistics of signals 

 and strays, especially within the hemisphere likely to be afifected by 

 the eclipse; it will endeavour to make provision for the transmis- 

 sion of special signals at times to be indicated on the forms ; and 

 it will ofifer for the consideration of the authorities controlling 

 stations near the central line a simple programme of work. The 

 discussion of the observations, and the comparison with the 



