OBSERVATORIES AND THE DATA OBTAINED. 71 
BALTIMORE, MARYLAND. 
Johns Hopkins University. Prof. Harry Fielding Reid, in charge of seismographs. 
Lat. 39° 18’ N.; long. 76° 37’ W.; altitude, 30 meters; distance, 35.74° or 3,973 km. ; 
chord, 3,909 km.; direction, N. 73° E. 
Foundation, clays and gravels, about 30 meters thick, resting on rock. 
Seismograms, sheet No. 1. 



The instrument used was a Milne horizontal pendulum; component, N: 60° W.; photo- 
graphic registration. T,, 14 seconds; V,6.1; J, 300 meters; e€, 1.03; r, 0.0 mm. j, Sheu 
lar displacement, 1 mm. = 0.83”; M, 255 em. L, 15.6 em. ~—-- 
First teres gs SACORY t RELIMINART ERCrEAE Max. Awp.rrupy. 
min. min, min. min. mm, 
N. 60° W. eee 19.4 25.2 31.6 31.8 to39.1 17 + 
Interval . 6.9 12.7 19.1 




If we assume that the wave period at Baltimore was the same as that at Cheltenham, 
namely, 13 seconds, we see that the large amplitude at this station is due to synchronism 
of periods of the waves and the pendulums. 
ALBANY, NEW YORK. 
Dr. John M. Clarke, State geologist. 
distance, 37.13° or 4,128 km. ; 
New York State Museum. 
Lat. 42° 39’ N.; long. 73°45’ W.; altitude, 26 meters; 
chord, 4,056 km.; direction, N. 67° E. 
Foundation, heavy blue clay with interbedded sand and gravel. 
Seismograms, sheet No. 8. 
The instruments used were Bosch-Omori horizontal pendulums, two horizontal com- 






ponents; mechanical registration on smoked paper. Constants for both components: 
Ty, 30 seconds; V, 10; J, 2,240 meters; M, 11.28 kg.; LD, 85.5 cm. 
Nd Baber aad sel A sep ig Beeueee oe ree Reet ycune: 
Tie as m 8. Mm. 8 min. mene 8s mm. 
(1) North component 21 30 29 04 33 00 | 33.5to 35.5| 34 30 32 
(2) East component 21 30 28 00 32 30 | 34.0 to 42 384 40 22 
Average 21 30 28 32 382 45 | 33.7 
Interval 9 02 16 04 20 17 | 21.2 




east, 2.7 hours. The times of the preliminary tremors 
are two or three minutes too late. The strong motion on the east component lasted about 
9 minutes, on the north component only 2 minutes; but the greatest amplitude was 
shown by the latter. The strong motion was not regular nor long enough to estimate the 
amplitudes of the earth’s motion. 
Duration, north, 2.1 hours; 
PORTO RICO (VIEQUES), WEST INDIES. 
Magnetic Observatory of U. 8. Coast and Geodetic Survey. O. H. Tittmann, super- 
intendent; P. H. Dike, magnetic observer. 
Lat. 18° 08’ N.; long. 65° 26’ W.; altitude, 40 meters; distance, 53.45° or 5,942 km. ; 
chord, 5,729 km.; direction, 8. 85° E. 
Seismograms, sheet No. 8. 
