E. S. Holden — Earthquakes in California. 397 



The time of the third and severest shock was 8 h. 48 m. 38 s. 

 p. M. Direction S. to N. (letter from XL S. Surveyor General 

 Irish). Two other observers say W. to E. — Grass Valley : felt 

 in the Idaho mine below the 1600 ft. level, Alta, May 2d. 

 "Very heavy, lasting 5 sec, from B. to W. (Chronicle, April 30). 

 — Grass Valley : the Orleans mine was flooded. The shock 

 was at 8:45 p. m. and very heavy (VII). It was preceded by 

 a loud noise. The duration was about 5 sec, and the wave 

 was E. to W. Clocks stopped, plastering fell, and also tops of 

 chimneys. — Nevada City : walls of courthouse cracked (VIII). 

 — At Marysville, Downieville, Truckee, Colfax and Sacramento 

 the shock was very strong (G. V. Tidings, April 30, May 2). — 

 Nevada City : two severe shocks at 8:48 p. m. preceded by a 

 deep rumbling sound. Direction N. — Dutch Flat ; 8:46 P. M., 

 severe from S. to 1ST. People were badly frightened. — Stock- 

 ton : four shocks at 8:40, from 1ST. to S. — Dixon, 8:45 p. M. — 

 Biggs: heavy shock "lasting 75 (?) seconds" [seven to five? 

 E. S. H.], at 8:45 (VII) plastering cracked, etc. — Santa Rosa : 

 slight shock at 8:45, N. and S. (III). — Truckee: 8:47, duration 

 two seconds, (S. F. Examiner, April 29). — Oroville : 8:45 P. M. 

 Short, quick shock.— S. F. : barely perceptible in third story 

 of 917 Pine street. No record on duplex seismometer in 

 basement (I). 



April 30, about 4 a. m. — Grass Valley : Tidings, April 30. 

 — Downieville : 3:40 a. m. two light shocks (IV), (S. F. Bul- 

 letin, April 30). 



May 4, 1:55 p. m. — S. F., 917 Pine street, decided shock, 

 not registered on duplex seismometer, J. R. J. — S. F., slight 

 shock (II) of a few seconds duration, (Bulletin, May 4). 



May 6, 9 h. 42 m. 22 s. p. m. (E. S. H.).— Lick Observatory : 

 sadden shock (III) E. S. H., preceded by a rumbling noise 

 (Porches..) (Registered on duplex seismometer). 



July 11, at night. — Susanville: slight shock (IV??), S. F. 

 Bulletin, July 13. 



August 14,' 9:57 a. m.— S. F., 917 Pine st. Intensity (II) on 

 R. F. scale. The duplex seismometer gives a looped trace on 

 the plate (magnified four times) 7 mm N.N.B. to S.S.W. (direc- 

 tion of first shock), 4 mm at right angles to this. The motion 

 of the earth was therefore S.S.W. to N.N.E. — Lick Observa- 

 tory : direction on the plate KO., of the earth S.S.W. The 

 trace is a wavy line (magnified four times) 8 mm long. N.N.E. 

 and S.S.W. with six waves l mm high at right angles to this. 

 Probably the shock was nearly vertical here. 



September 10, 1:53 a. m. — S. F., 917 Pine street : slight shock 

 (II) not registered on duplex seismometer, J. R. J. — Oakland: 

 slight shock, C. Burckhalter. Three shocks at 1:50 a. m. in 

 quick succession, attended by noise ; windows did not rattle 



