62 REPORT OF THE CALIFORNIA EARTHQUAKE COMMISSION. 
BERKELEY, CALIFORNIA. 
Students’ Astronomical Observatory of the University of California. Prof. A. O. 
Leuschner, director. 
Lat. 37° 53’ N.; long. 122° 16’ W.; altitude, 97 meters; distance, 0.46° or 51 km.; 
direction, 8. 68° E. 
Foundation, solid rock. 
Seismograms, sheet No. 3. 
The instruments used were (1) Ewing three-component seismograph, (2) Ewing duplex 
pendulum, V, 4. The recording plate of the three-component seismograph was raised 
off its bearings and failed to revolve, and the brackets recording horizontal motion were 
so disarranged that no reliable record was made; but the weight recording vertical mo- 
tion showed a maximum displacement just within the range of the instrument, namely, 
76 mm., and as the magnifying power was 1.7, and the friction so great that it was practi- 
cally dead-beat, we may fairly conclude that the maximum vertical range of the ground 
was about 45 mm., and the amplitude half as much. 
The duplex pendulum record is greatly confused and much affected by the stops which 
limit the displacement of the pendulum; but by a careful study of a greatly magnified 
record, Professor Leuschner has succeeded in working out the early part of the motion 
which is reproduced separately on the left of the complete seismogram. The directions on 
the seismograms show the directions of the earth’s movements. As the magnifying power 
is 4, we see that there was first a movement of the earth of 4.5 mm. towards the east, that 
is, away from the origin, followed by a movement of 6.5 mm. to the north. It then swung 
towards the west and back to the southeast. The character of the movement from this 
point can be more easily understood from the seismogram than from a verbal description ; 
it is soon lost in the confused record which shows a great deal of irregularity; this must, 
however, partly be due to the influence of the stops which limit the movements of the 
pendulum. The stops limited the motion so that an earth-amplitude of only 11 mm. 
was recorded, far less than was actually experienced. 
OAKLAND, CALIFORNIA. 
Chabot Observatory. Prof. Charles Burckhalter, director. 
Lat. 37° 48’ N.; long. 122° 17’ W.; altitude, 4 + meters; distance, 0.48° or 53 km.; 
direction, S. 59° E. 
Foundation, alluvium. 
Seismograms, sheet No. 3. 
The instrument used was a Ewing duplex pendulum, V, 4. The seismogram is too con- 
fused to give details; but we see clearly that the movement of the pendulum was limited 
by the nature of the instrument; the movement seems to have been in nearly all direc- 
tions, and more or less irregular, tho this irregularity was undoubtedly in part due to the 
pendulum’s striking against the side of the case. The beginning of the movement can not 
be made out on the seismogram. The earth-amplitude recorded is only 10 mm., much less 
than was actually experienced. 
YOUNTVILLE, CALIFORNIA. 
Veterans’ Home. F. M. Clarke, superintendent. 
Lat. 38° 24’ N.; long. 122° 22’ W.; altitude, 50 meters; distance, 0.49° or 54 km._ 
direction, N. 45° E. 
Foundation, alluvium over trachite. 
Seismograms, sheet No. 3. 
