3 6 ° 



NATURE 



[June 5, 191 3 



lines of tracks and many points and crossings, the 

 equipment of a single-phase locomotive costs more 

 and weighs more than that on any other system, and, 

 last but not least, there is a great risk" of serious 

 disturbance to telephone and telegraph lines in the 

 neighbourhood due to both electrostatic and electro- 

 magnetic induction. 



In three-phase working, as used on most of the 

 Italian electric railways, the second of these three 

 disadvantages does not obtain, but the first disadvan- 

 tage is accentuated owing to the need of two live 

 conductors for each line of track, and the possible 

 effect on the telegraph and telephone lines is the same. 

 The high-tension continuous-current system is grow- 

 ing in favour, therefore, but it surfers from other 

 disadvantages, although it would certainly appear to 

 fulfil most completely the conditions required in a 

 large number of cases. Standardisation is, of course, 

 desirable for railway working, owing to the through 

 traffic from one line to another, and many suburban 

 lines are already equipped on the medium-pressure 

 third-rail system. In the full discussion of the sub- 

 ject in Paris, the relative values of these and other 

 technical point-, were weighed. 



Among the other papers read at the Paris meeting 

 was one by Mr. W. Slingo, engineer-in-chief of the 

 British Post Office, on certain auxiliary apparatus in 

 telephone exchanges. He described a "class of appa- 

 ratus, originally evolved in connection with automatic 

 telephone exchanges, which is now being applied by 

 the Post Office in some of the manual exchanges in 

 London to assist in the distribution of traffic. In 

 ordinary exchange working, when a subscriber re- 

 moves his telephone from the hook, a lamp corre- 

 sponding to his number glows, being actuated through 

 a relay, and the operator to which this number" is 

 allotted, or one of the operators on either side of 

 her, places a plug in the subscriber's answering jack 

 immediately by the lamp, and makes the necessary 

 connection. In spite of there being three operators 

 who can attend to any subscriber in the busy hours 

 of the day, there is nevertheless a certain amount of 

 time in which each operator is not fully engaged. 

 In the new "Avenue" exchange, an endeavour to 

 level the work of the operators was made by using 

 "ancillary" jacks for each subscriber, multipied over 

 two other sections of the board, so that any one of 

 nine disengaged operators could take any call." In the 

 new system, however, this distributing of the calls to 

 a free operator is made absolutely automatic. The 

 allotment of groups of subscribers to definite operators 

 is discontinued. As soon as a subscriber lifts his 

 telephone from the hook, an automatic switch at the 

 exchange end of his line selects a line leading to 

 anv operator who is idle for the moment, the calling- 

 lamp at her position glows, and she immediatelv 

 answers the call. 



Two lectures were given on the closiner dav of the 

 meeting, one, by M. Georges Claude, 'on the 

 neon light, and the other, by Commandant Ferried on 

 the Eiffel Tower time signals. A discharge in a tube 

 of neon gas gives a very pleasant red or orange-red 

 light, which is. however, absolutely devoid of blue 

 rays. M. Claude proposes to combine the use of 

 these tubes with mercury-vapour tubes, and as the 

 latter are rich in blue rays and devoid of red, a more 

 or less white light is obtainable. A difficultv arises 

 in the fact that while the neon tube requires high- 

 tension alternating-current for the luminescent dis- 

 ( barge, the mercurv-vapour tube requires low-pressure 

 continuous current. It appears, however, that M. 

 Claude uses in his "correcting" tubes both neon and 

 mercury, which, he said, renders them suitable for 

 alternating current (the exact physical explanation of 



NO. 



1275, VOL - 9 1 ! 



this was not given in the lecture), so that both tubes 

 can be connected to the same circuit. He gave the 

 efficiency of the combination at about o-S to 0-9 per 

 candle. 



Commandant FerrieVs lecture on the Eiffel Tower 

 time signals was extremely interesting, but as this 

 subject was described in detail in Nature of March 

 13, it is unnecessary to do more than mention it briefly 

 now. The time signals at present are sent out twice 

 daily, from 10.44 t0 IO -49 a.m., and from 11.44 to 

 11.49 P- m - From July onwards there will be some 

 alteration in the times for sending out these signals 

 and also in the character and sequence of the warn- 

 ing signals. The times for the exact time signals 

 will then be altered to 10 a.m. and midnight. To 

 enable the greatest possible accuracy of observation, 

 a series of 180 short dots regularly spaced at one 

 second less about 1/50 of a second apart are sent 

 out immediately before the ordinary night signals. 

 To facilitate counting, the 60th and 120th dots are 

 omitted. ' This series of dots is received by the Paris 

 Observatorv and other observatories, in each of which 

 the operator listens at the same time to the beats 

 of the master clock or another seconds chronometer. 

 The two sets of beats thus constitute an " acoustic- 

 vernier, " and during the time that the 180 wireless 

 dots last, three coincidences spaced thirty seconds 

 apart occur between the wireless dots and the beat 

 of the clock. By noting the time indicated by the 

 chronometer at the moment of coincidence, as well as 

 the number of wireless impulses heard before the 

 coincidence occurs, it is possible to calculate the time 

 of the chronometer at the receipt of the first wireless 

 impulse. For instance, if the Greenwich mean time 

 of a coincidence was 23I1. 30m. 25s., and the number 

 of the stroke at coincidence was 42, the time of the 

 first beat will have been 23!!. vm. 25s. minus 

 41 (1 — 1/50) seconds = 23h. 29m. 44-825. 



PROF. BERGSON ON PSYCHICAL 



RESEARCH. 



DROF. HENRI BERGSON delivered his inaugural 



-'- address as president of the Society for Psychical 



Research on Wednesday, May 28, in the /Eolian Hall, 

 New Bond Street. At the close of the address, which 

 was delivered in French, and held the close attention 

 of the company for nearly an hour and a half, Mr. 

 A. J. Balfour, a past-president of the society, rose to 

 express the thanks of the hearers, and characterised 

 the address as the most interesting and illuminating 

 one that the society has ever received. When we 

 recall that Mr. Balfour himself, Prof. William James, 

 Lord Rayleigh, the late F. W. H. Myers, and many 

 other distinguished men have held the office of presi- 

 dent, we can but feel that M. Bergson has justified 

 both the choice of the society and his reputation as 

 a maker of new thought. 



M. Bergson took as his principal theme a study of 

 the nature of the prejudices against the work and 

 methods of the society; in fact, against its very exist- 

 ence — prejudices felt, not by the uninformed and un- 

 learned, but by men of science, keenly desirous to 

 extend the bounds of human knowledge. He attri- 

 buted the objection to the methods which the experi- 

 menters in psychical research were forced to adopt 

 in order to pursue their investigations — methods 'akin 

 to_ the judicial, the historical, or even to those of the 

 criminal detective, but, since the Renaissance, foreign 

 to the world of natural and. experimental science. The 

 great development of mathematical science, based on 

 the recovery of Greek learnine, and carried forward 

 by such men as Kepler, Galileo, and Newton, had 

 given to the modern mind the conception of scientific 



