152 MR. It. D. OI.DHAM ON THE PROPAGATION OF 



Mountains to the southwards of Jisak and Ura Tube, in a region from which infor- 

 mation is unattainable. It may be taken as in about 39 N. Lat. and 68 E. Long. ; 

 this will certainly be nearer the truth than assuming the position of Jisak as that of 

 the epicentre, and may be taken as correct within a limit of error of 1 of arc. 



For the time we have only the observations at Tashkent. According to the 

 director of the observatory there, as quoted by Dr. AGAMENNONE, the times at Tash- 

 kent were 8 h 7 m 30 s P.M. and 10 h 15 m 22 s P.M. respectively. As the distance from the 

 epicentre is about 320 kiloms., the time of origin of the shock would be about 2 m 

 before its arrival at Tashkent, taking the rate of propagation as 3 kiloms. per second. 

 This would give the G.M.T. times of origin as 15 h 28 m and 17 h 36 m respectively, 

 times which may be taken as correct within one minute of error. 



1st Shock of 15 h 28"'. 



Nicolaiew. 15 h 40 commencement, maximum at 15 h 45 m , end at 16 h 24 m . 



Potsdam. 15 h 44 m commencement, at 47 m a slight increase, at 50 m , another sudden 

 increase and the trace disappears shortly after ; end about 1 7 1 '. 



Ischia. The horizontal pendula were disturbed as early as 15 h 15 m 12", but this 

 was evidently the same disturbance as affected the instrument at Catania. The first 

 decided increase was at 15 h 42 m 33" on the N. S., and 42 m 36 s on the E. W. com- 

 ponent, they decrease after 3 minutes, and at 15 h 50 the oscillations are irregular, 

 but grow more regular and longer, reaching a maximum at about 16 1 '. It is not 

 possible to make out from the description, whether there was a defined maximum, but 

 probably not. End at 16 1 ' 35 m . 



Catania. The disturbance commenced at 15 1 ' 15 m 50 s on the N.W. S.E. com- 

 ponent, and at 15 15 s on the N.E. S.W. ; this is some 13 minutes before the time 

 of origin of the shock, and this disturbance must be attributed either to some other 

 earthquake, or to tremors of a character which were not felt within the seismic 

 area. In either case they cannot be referred to any of the three phases under 

 discussion. 



At 15 h 42 53 s on the N.W. S.E., and at 42'" 47 s on the other component the 

 disturbance becomes well marked. No definite phases are referred to but the 

 maximum departure from normal was attained at 16 h O m 50 s on the N.W. S.E., 

 and at 16 h l m s on the N.E. S.W. component. End at 16 h 14 m 7 s on N.W. S.E., 

 and at 16 h 13 m 27 s on N.E. S.W. component. 



Rocca di Papa. Grande sismom. ; commencement of disturbance at 15 h 50 m on 

 E. W., 52 m on N. S. component. The horizontal pendulum commenced at 15 h 50"' 

 on the N. S. component. Maximum from 15 h 55 to 58 m , end at 16 h 5. The record 

 of the other component shows nothing. 



Rome. The sismom. medio. showed at 15 h 38 m 30 s some minute undulations and 

 nothing more till 47 ra 30 s . A small isolated group appears later with a maximum 

 at 16 h 2 m 10 s . 



