OBSERVATORIES AND THE DATA OBTAINED, 81 
POTSDAM, GERMANY. 
Kgl. Preuszisches Geodatisches Institut. Prof. Dr. O. Hecker, in charge of seismo- 
graphs. 
Lat. 52° 53’ N.; long. 13° 04’ E.; altitude, 90 meters; distance, 81.35° or 9,042 km.; 
chord, 8,303 km.; direction, N. 25° E. 
Foundation, sand. 
The instruments used were: 
Rebeur-Paschwitz pendulums, photographic registration. Seismograms, sheet No. 4. 
(1) North and (2) East components: 7, 18 seconds; V, 36; J, 2,900 meters; ¢, 2.5; 
M,70gm.; L,9cm. (?). 
Wiechert inverted pendulum, two components; mechanical registration on smoked 
paper. Seismograms, sheet No. 5. 
(3) North component: 7, 14seconds; V, 133; J, 6,500 meters; « 5; M, 1,000 kg.; 
L/, 49 meters. 
(4) East component; 7’), 14 seconds; V,130; J, 6,350 meters; e,5; M,1,000kg.; L/, 
49 meters. 












First SECOND R P 
PRSLIMINARY PRELIMINARY wives? 5 ee Max, AMPLITUDE, | Pxrriop. 
ie ae min. min. Hee 8: m 8. mm. sec. 
(1) North component| 24 50 35.6 52.3 Fe 
(2) East component a See, 52.0 ewe peek: nice 60 23 
m. 8. Mm. 8. 
(3) North component| 24 50 Sta, CS OLeeLS 54 50) 56 40 85 + 28 
(4) East component 24 51 35 05 51 40 54 50 | 56 07 80 + 28 
Average .. . 24 50 SOM 51 49 54 50 
Mmterval ~~. .: 12a 2 2mOD 39 21 42, 22 

Duration, 6 hours. 
On account of the overlapping of the records on the seismogram of the East component 
of the Rebeur-Paschwitz instrument the beginning of the first two phases can not be made 
out. There was a shifting of the median lines at about 14°, after which it exactly overlay 
the earlier line. ‘The copyist has made the terminal part of the curve pass into the earlier 
part at about 15° 33™ (135 34" ). The maximum amplitudes of the earth, as shown 
by the various instruments, approach the following values, tho the movements were not 
sufficiently regular to make the measures exact. (1) 1.7 mm.; (8) 2.7 mm.; (4) 2.2 mm. 
These maximums all occurred between 13" 56™ and 135 57™. The recording point 
passed its limits and ceased to record on (4) at the time when the amplitude was measured. 
(3) indicates an earth-amplitude of 3.65 mm. at 13" 53™, during the long waves; the east 
component at that time is not sufficiently regular to yield a measure, but the total value 
must be greater than 4. 
GOTTINGEN, GERMANY. 
Geophysikalisches Institut der Universitat. Prof. Dr. E. Wiechert, director. 
Lat. 51°33’ N.; long. 9° 58’ E.; altitude, 270 meters; distance, 81.36° or 9,046 km.; 
chord, 8,304 km.; direction, N. 28° E. 
Seismograms, sheet No. 12. 
The instruments used, all having mechanical registration on smoked paper, were: 
(1) Wiechert inverted pendulum, north component: 7, 1.48 seconds; L’, 0.543 meter; 
V, 2,100; J, 1,140 meters; ¢, 8.0; r,0.8mm.; M, 17,000 kg. 
Wiechert inverted pendulum, two components : 
a 
