EARTHQUAKES ON THE PACIFIC COAST 145 



1889. November 15; 7:55 p. m. 



East Oakland: a slight shock (II) felt by three persons in the 

 vicinity. No record on seismograph, hence motion was probably 

 vertical. The shock was felt in San Francisco, and noticed in 

 the daily papers. — F. G. Blinn. 



San Francisco, 7h. 55m. p. m. Light shock. Duration 2 seconds. 

 — T. T. 



Healdsburg: " a very severe shock of earthquake was felt in this city 

 last night at 7.55. It was the heaviest experienced here in many 

 years." — S. F. papers. 



1889. December 2; 6:30 p. m. 



East Oakland: the seismograph record (magnified) shows a number 

 of nearly circiilar tracings about two millimeters in diameter, 

 inclosing short irregular lines in different azimuths. The time 

 was noted by a neighbor, as I was not at home when the shock 

 occurred. — F. G. Blinn. 



1889. December 14; 5:30 a. m. 



Carson: E. W., light.— C. W. F. 



Note by Dr. Keeler. — " The present bulletin is to be regarded as little 

 more than a list of recorded earthquakes in California in 1889 

 and a collection of such data as are available for estimating the 

 intensities of the different shocks. Accurate observations of 

 earthquakes are difficult to obtain, as the instruments employed 

 require some skill in the observer and a certain amount of atten- 

 tion to be always in working condition. The sensations experi- 

 enced during an earthquake shock vary greatly for different 

 persons, and descriptions based on the feelings alone are apt to 

 be extremely unreliable. It is hoped, however, that other sta- 

 tions provided with suitable instruments can be established in 

 different parts of the State, and that eventually sufficient data 

 can be accumulated for a more complete study of earthquake 

 phenomena on the Pacific coast than the material now available 

 would permit." These remarks apply to the whole of the present 

 volume. — E. S. H. 



EARTHQUAKES ON THE I'ACIFIC COAST, 1890. 



1890. January 15; Mount Hamilton; 5:05 + lm. a. m. (Prof. Holden). 



Intensity zm V. — Mr. Keeler noted the time by watch, P. S. T.^ =: 

 5.05.3 ± 10s. a. m. Intensity =: IV. Time by earthquake clock z= 

 5.02 a. m. 



The record of the duplex seismograph shows the actual displace- 

 ment of the pendulum bob to have been 2.6 mm., in a direction 



' P. S. T. — Pacific slope time, which is Greenwich time less 8 hours. 

 10 



