( 246 ) 
As the seismograms bear an entirely different character as the 
waves proceed from the centrum of disturbance, an exact comparison 
of the epochs of commencement, maximum effect and end offer, 
up to the present time, considerable difficulties. 
Moreover in most cases the epochs of beginning and termination 
cannot be sharply indicated, as the seismograms generally exhibit 
a gradual increase and decrease of motion. An exact measurement 
of the velocities of propagation will be possible only when a reliable 
method has been found of analysing the compound movement in its 
elementary constituents. 
With the hypothesis, that the vibrations have travelled along 
paths approximating the chords through the earth, we find that 
the velocity of propagation has been about 10 K.M. per second; 
the distance between Strassburg and Amahei being 10402 K.M. 
As the distance between Batavia and Amahei is 656 K.M., the 
exact local time of the earth-quake can be fixed at 1» 42™,2. 
B. Concerning the other earth-quake, observed also at Batavia 
as well as at Strassburg, the following data are provided by the 
seismograms: 
Strassburg. Batavia. 
aart 20h 58,9 beginning. 
inary m 
cance 215 §,2 maximum. 
September 10 
1899. 21h 54,3 beginning. 22h 7,0 
Greenwich time 21h 58,9 maximum 22h 54,5 
24h 28,9 end 23h 19,5 
m , m 
\ Duration 2h 34,6 Ik 12,5 
From these records we may conclude that the centre of the disturbance 
is situated at a greater distance from Batavia than from Strassburg ; 
firstly because preliminary tremors have been registered at the latter 
place about 21"; secondly because the epoch of maximum disturb- 
ance at Batavia is about one hour later than at Strassburg, and 
thirdly because the duration is considerable less at the former than 
at the latter station. 
The last argument is, however, questionable, owing to the diffi- 
culty of fixing the characterizing epochs. In , Nature“ it is noted 
down, (presumably by Prof. Minne from the isle of Wight) that 
seismic disturbances occurred on the 3rd, 10% and 17% of September. 
No indications of the exact time of occurrence are given, but it is 
stated that the centre of disturbance is in Alaska. 
