14 REPORTS ON THE STATE OF SCIENCE.—1917. 
paths, but there is no PS, or higher term. On the other hand, SP with an 
infinite series SP,, may begin at A =11°, and there is only one path for each 
member until 4 =99°, beyond which there are two possible paths for each 
member. 
In the range A =11° to 99°, the manufacture of Rayleigh waves goes on. 
Actual figures for the earth will, no doubt, modify these numbers in the 
sense that they will be smaller than those for a uniform earth, and careful 
analysis must be made to sce if the phenomena of the seismogram are 
consistent with a focus as deep as 1,300 kms. 
Meanwhile, it appears desirable to draw attention to this direct 
inference from Galitzin’s measurements. 
Prelinanary Report on Terrestrial Magnetism. 
By Dr. Coartes Curee, F.R.S. 
(Prepared at the request of the Organising Committee of Section A.) 
$1. THERE are two existing agencies which should be taken into 
account by everyone anxious to promote any new or large scheme of 
work, especially co-operative work, in terrestrial magnetism, viz., the 
International Magnetic Committee and the Department of Terrestrial 
Magnetism of the Carnegie Institution of Washington. In most countries, 
terrestrial magnetism is officially regarded as a branch of meteorology, 
and most professional terrestrial magneticians are attached to the meteoro- 
logical services of their respective countries. The International Magnetic 
Committee thus comes to be an offshoot of the International Meteorological 
Commission. The latter is composed of the directors of the meteorological 
services of the principal countries, but the International Magnetic Com- 
mittee is a more numerous and heterogeneous body. The list published in 
connection with the last meeting of the International Magnetic Committee, 
held in 1910, at Berlin, contained the following names: Rykatchefi* 
(President) and Dubinsky (Russia); Schmidt* (Secretary) and Messer- 
schmitt (Germany); Bauer, Faris, and Mendenhall (United States) ; 
Angot* (France) ; Riicker, Schuster, and Chree* (Great Britain); Liznar 
and Kesslitz (Austria) ; Palazzo (Italy) ; van Everdingen* (Netherlands) ; 
Carlheim Gyllenskéld* (Sweden); Tanakadate (Japan);  Stupart 
(Canada) ; Bigelow (Argentine). The British representation has suffered 
a severe loss in the death of Sir Arthur Riicker. 
The International Committee can pass resolutions, but their doing so 
carries no compulsion with it. A number of definite opinions have been 
expressed, e.g., as to terminology, data to be published, time to be 
observed and sensitiveness of magnetographs, some of which have exerted 
a considerable influence. Besides debating and passing resolutions, the 
International Committee has got certain things done whose utility is 
penerally recognised. Probably the most successful of these is the scheme 
of international magnetic ‘quiet’ days, the organisation in connection with 
* Those to whose names an * is attached compose the working Bureau, which is 
more especially intended to interest itself in current topics. 
