104 REPORT OF THE CALIFORNIA EARTHQUAKE COMMISSION. 
Duration, 3 hours. The time of the beginning is evidently too early; the smallness 
of the motion makes it quite impossible to determine the precise time. The north- 
northwest component (not reproduced) gives a record very similar to the other, but with 
a somewhat smaller amplitude. The maximum instrumental amplitude is at 14° 08.0", 
when the earth-amplitude was (ENE.) 0.44 mm., (NNW.) 0.4 mm., or a possible total 
of 0.6 mm. Data are not at hand to determine the vertical earth movement, tho the 
instrumental amplitude was 0.25 mm. A larger earth-amplitude occurred during the 
long waves; we find, at 14" 01.0", earth-amplitudes (ENE.) 0.75 mm., (NNW.) 0.45 mm., 
or a possible total of 0.87 mm. If instead of a short-period pendulum there had been 
one with a period in the neighborhood of 25 seconds, the record would have been very 
large at this time; and if the period had been about 20 seconds, the record would have 
been very large at 14" 08.0"; as it is, with a period of 2.4 seconds, the record is quite 
small. The strong contrast between the seismograms of Manila and that of Potsdam, on 
the same plate, is principally due to the periods of the pendulums at the respective 
places. At Potsdam the period was 18 seconds. 
TADOTSU, JAPAN. 
Meteorological Observatory. N. Maeda, director. 
Lat. 34° 17’ N.; long. 133° 46’ E.; altitude, 6 meters; distance, 101.30° or 11,262 
km.; chord, 9,852 km.; direction, N. 55° W. 
The instrument used was an Omori horizontal pendulum; mechanical registration 
on smoked paper. M, 10 kg.; V, 20; Z, 75 cm.? 
First preliminary tremors, 25" 07°; interval, 12 minutes 39 seconds. 
CAIRO, EGYPT. 
Helwan Observatory. H.H. Wade, director. 
Lat. 29° 52’ N.; long. 31° 20.5’ E.; altitude, 115 meters; distance, 107.92° or 11,998 
km.; chord, 10,302 km.; direction, N. 23° E. 
Foundation, directly on Eocene limestones; in the desert about 5 km. from the Nile. 
Seismograms, sheet No. 1. 
The instrument used was a Milne horizontal pendulum, east component; photographic 
registration. T,, 15 seconds; V, 6.1; J, 340 meters; ¢, 1.054; angular displacement, 
1 mm. = 0.5”; M, 255 gm.; L, 15.6 cm. 





F P Ss PrRE- 
be pr ptase pecnietes: Max. coe 
TREMORS. | TREMORS. 
min. min. mm. 
East component . .| 31.0? 39.0? 14° 34.0") 4.0 
Interval = es et8:57 26.5? 



Duration, 3.5 hours. Only a drawing of the seismogram was available; this and the 
indefinite character of the seismogram make it impossible to obtain accurate time deter- 
minations of the various phases. The beginning of the first preliminary tremors are 
evidently too late, but the time of the second preliminary tremors seems about right. 
1 The constants are taken from Professor Omori’s Report on the Great Indian Earthquake. “Eub: 
Karthquake Investigation nop meer in Foreign Language, No. 24.”” The time is taken from Bulletin 
of the same Commission, vol. 1, 
