EARTIIQIAKES OX THE PACIFIC COAST 33 



The atmospheric coiulitions prevailing in tlie vallov previous to 

 the shock, as viewed by me from an elevation of 4.500 feet were 

 very peculiar.— A. W. Sehorn.) 



Magalia; 0:2():50 p. ni. YI. 



1903. July 30; Elsinore. Eedlan.ls, Riverside. Salinas, San Bernardino. San 

 Jacinto, Uplands. 



(San Bernardino. The earthquake at 9 p. m. on the 30th was .piite 

 severe and lasted about twenty seconds.— Dr. A. K. Johnson.) 



1903. August 2; Alameda, Boulder Creek, Calistoga, Campbell, ]<:iinwood. 

 Fresno. Hollister, Kentfieid, Lick Observatory, Lodi, Mills Col- 

 lege, Mount Tamalpais, Oakdale, Peachland, Rio Vista, Sacramento, 

 Salinas, San Francisco. San Jose, San Rafael, Santa Cruz, Santa 

 Rosa, Sonoma, Stockton, Suisun, Summerdale, Tequisquita Rancho, 

 Yosemite Yalley. 



Oakland; Chabot Observatory. Observers, C. B. and S. W.; 10:-49:29 

 a. m.; duration, 31 seconds; direction, south to north, east to west; 

 intensity IV. There were two distinct shocks. The first, south to 

 north, lasted about 20 seconds; then, after a quiet interval of 

 3 seconds, a shock from east to west lasted 8 seconds. Stopped 

 mean-time clock 10:49:42 a. m. 



Xiles; 10:0.j p. m. and 10:59 p. m. — Wm. Barry. 



Napa; 10:42 p. m. Lively.- W. H. Martin. 



Lick 01)servatory; 11:36:30 p. m. 



1903. August 2; Lick Observatory. R.-F. VII or VIII. The most severe 

 shock since the establishment of the Lick Observatory occurred 

 on the night of Sunday, August 2, 1903. The time of beginning 

 of the first shock was recorded by various observers as follows: 

 10:49:21—3 p. m.— Aitken; 10:49:21— Yogt; 10:49:15— Perrine. 

 Smaller vibrations lasted a few seconds, followed by 15 or 20 

 seconds of very violent shocks, generally in an east-west direc- 

 tion. Strong vibrations continued 10 seconds longer. This shock 

 proved too severe for the seismometers of the Lick Observatory. 

 The duplex recorded the earlier vibration, but was thrown out 

 of adjustment by the heavier shock. The Ewing plate failed 

 to rotate, but the indicator moved about, practically with the 

 result that the east-west pen was thrown entirely oif the disk. 

 The motion of the earth seems to have been about half an 

 inch. None of the astronomical instruments suffered damage. 

 Beyond numerous cracks in plastering, nothing will remain to 

 betray the intensity of the disturbance. Several chimneys on 

 brick houses toppled over. Evidence points to Hall's Valley as 

 the probable center of seismic activity. As in the case of the 

 shock of 1868, minor vibrations have been recorded at small in- 

 tervals as follows: August 2, 11:36:30 p. m. R.-F. IIL Light 

 shock, lasting 1 or 2 seconds. August 3, 3:22:41 p. m. R.-F. TI. 

 Single vertical jolt. August 8, 4:17:14 p. m. R.-F. I; duration. 



