ON SEISMOLOGICAL INVESTIGATION. 269 



every hour raises a screen which eclipses the beam of light from a fixed 

 mirror in the pendulum case, and in this way gives on the datum line a 

 series of time marks. With a period of 12 seconds one millimetre deflec- 

 tion on the record corresponds to a tilting of 0''*058. 



After visiting the director of the observatory, Professor Becker, who 

 for so many years carried on observations with Von Rebeur's pendulum, 

 Dr. Gerland showed me the site of the Seismologicaf Institute, which next 

 year will be erected within the University grounds. The Government 

 grant for this building is 70,000 marks, or 3,.500^., with an annual allowance 

 of 5,500 marks, or 2751., for its maintenance. It is expected that the latter 

 sum will be increased. To commence with, the instruments which it is 

 proposed to instal are Dr. Ehlert's pendulums, a Vicentini pendulum, and 

 a Milne pendulum similar to those established by the B.A. Committee. 



As a correction and extension of the second and third paragraphs of 

 the Report of 1897, p. 129, I learned from Dr. G. Gerland that the idea 

 of an international organisation for the observation of earthquakes was 

 first brought forward by the late Dr. E. von Rebeur-Paschwitz and him- 

 self in October 189-4. At the end of 1894 and the beginning of 1895 they 

 prepared a definite appeal to the scientific world to carry out their sugges- 

 tions : this appeal, written by Dr. von Rebeur, was subscribed by a 

 sei'ies of prominent learned men and was published in the ' Beitrage zur 

 Geophysik,' edited by Professor Gerland, Band II. p. 773. 



After the death of Dr. von Rebeur Dr. Gerland naturally felt pledged 

 to continue the work which he had co-operated to inaugurate. Subsequent 

 issues of the propositions therefore appeared under the name of Dr. Ger- 

 land, who in 1895 brought the same to the notice of the International 

 Geographical Congress in London. 



Briefly stated, they were to establish a centre for the collection and 

 pul^lication of reports relating to all earthquakes which are from time to 

 time recorded throughout the world. 



It was proposed to issue these reports in Dr. Gerland's geophysical 

 journal. 



The most important records would be those obtained from horizontal 

 pendulums, ordinary long pendulums, and bifilar pendulums, and as a 

 commencement it was suggested that ten observing stations should be 

 established round the world. 



The positions of these stations were chosen with regard to Japan, from 

 which country large earthquakes frequently radiate. 



The Congress passed a resolution respecting the desirability of carrying 

 out Dr. Gerland's proposal. 



Very shortly we may expect to see the publication of the first part of 

 the great work which Dr. Gerland has undertaken, in connection with 

 which the reports issued by this committee will undoubtedly prove an 

 assistance. 



CON'CLUSION. 



In connection with the instruments which I saw in Italy and at Strass- 

 burg, I will first consider those which are employed to record local 

 disturbances or the short-period movements which we can feel. 



In Japan I once used a pendulum carrying 80 lb., and 40 feet in 

 length ; two pendulums, each of which carried 32 lb., and were 36 feet in 

 length, and very many 3 or 4 feet in length, carrying heavy disc-like bobs. 



Some of these recorded by light pointers resting on stationary or 



