ON SEISMOLOGICAL INVESTIGATION. 181 
‘The Committee for investigating the Earthquake and Volcanic Phenomena 
of Japan,’ and ‘The Committee on Earth Tremors,’ should not be re- 
appointed individually, but that the whole subject should be referred to a 
new committee (consisting largely of the members of the old committees), 
which should be called ‘The Committee on Seismological Observations.’ 
This Committee now presents its first report, and in doing so desires to 
record its thanks to the Secretaries of the two old committees for having 
continued their work as joint Secretaries to the new one. Statements 
of what they have been doing form the bulk of the present report. 
The Committee, however, thinks that it would be well, in this its 
first report, to state definitely what it hopes to accomplish, and how far it 
thinks that the British Association should go. It has long been an un- 
written rule, that the Association should initiate work, but should not 
charge itself with its maintenance. That is precisely what your Committee 
desires. Now that it has been proved that any important earthquake is 
felt all over the globe, the Committee considers that arrangements should 
be made for the record and study of these movements. Your Committee 
believes that such records may prove as important as those of, e.9., 
terrestrial magnetism, and, just as we have magnetic observatories in 
various parts of the world, so in its opinion should there be seismological 
ones. But, before advocating their erection, it is essential that a decision 
be arrived at as to the form and the degree of sensitiveness of instrument 
to be recommended. 
This, and correspondence connected with the organisation of the 
system, is the work which the Committee desires to complete. Previous 
reports, and the appendices to the present one, show how much has been 
done in this direction, but the Committee wants to do much more. It 
wishes to place side by side four good patterns of instruments, and to 
compare and study their records. When this is done it hopes to receive 
the support of the Association in approaching Government with the view 
to the establishment of a limited number of instruments identical in 
' sensitiveness, in this country, in India and in the Colonies, and of a small 
central office, at Kew or elsewhere, for co-ordinating and publishing the 
results. As far as the Committee can at present judge, the equipment 
of each station with complete apparatus for continuous photographic record 
would not exceed 1007. For the experimental work of the coming year 
the Committee have one instrument, and can have the use of another 
_ {constructed under a grant to Professor Milne by the Royal Society) ; it 
wishes to purchase two others, and will have to build piers, &c., and pay 
‘for photographic necessaries and an assistant to run the instruments, 
‘which, altogether, would probably cost over 200/. Your Committee 
thinks it desirable that to meet unforeseen items it should have 250/., but 
without 200/. the work cannot go on. 
Report by Professor Joun Minne, /’.2.S, 
I. Notes on Instruments which will record Earthquakes of Feeble Intensity. 
What we desire to record are preliminary tremors of small amplitude 
followed by quasi-elastic waves of comparatively large amplitude. 
Within a hundred or two hundred miles of an origin, the former of 
these have periods varying between } and ;!; of a second. Ata great 
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