EARTHQUAKES ON THE PxYCIFIC COAST 139 



18S!». Jnly 9-10; during' night. 



Carson City. Nevada: slight shoclc. In all these records the prin- 

 <'ipa] motion is west-northwest and east-southeast. 



18SJ). Jnly lO; and inrecedlng- days. 



Arroyo Grande. San Luis Obispo County: the following- report is 

 from the San Jose Times: 



The territory around Los Olivos has been troubled with an earth- 

 quake the past few days. Sunday there were six distinct shocks, 

 one of which rattled the dishes off the shelves. The hardest 

 shoe]'; took place at 3 o'clock this morning. The drug-gist at 

 Santa Ynez has removed his bottles from the shelves to the floor. 

 Fo\ir years ago a burning volcano was reported at Lookout Moun- 

 tain, on the south side of Santa Maria valley, which was decided 

 to be a burning asphalt bed. 



1889. Jnly 35; 10:8 p. ni. 



Mount Hamilton: sharp shock. Rattled pictures on the wall. Time, 

 10:8.2 (V). — E. S. H. A light quivering shock, followed by a sevei-e 

 shock, shaking the observatory building, at 10.7.59. — E. E. B. 

 Time, 10.7.59.— J. M. S. Time, 10.7.58.— C. B. H. Generally felt 

 by those on the mountain who were awake and not engaged in 

 some occupation which would disturb the attention. It did not 

 seem to me as strong- as others we have had (IV). — J. E. K. 



Record obtained on both seismographs. The Ewing machine shows 

 maximum (magnified) double amplitude = one millimeter in 

 north and south direction, with period =: one-third second. Cor- 

 responding- east and west motion very small, and vertical com- 

 ponent hardly perceptible. The vibrations are almost indistin- 

 guishable at fifteen seconds after the time of starting of the 

 plate. The duplex pendulum record agrees well with this, but 

 shows a slightly greater amplitude (magnified four times, about 

 2 millimeters). The computed intensity is 53 or R.-F. (II-III). 



1889. Jnly 31; 4:46:45 a. m. 



Central California, Mount Hamilton: shock wakened sleepers. Time 

 4.46.45 a. m. (V).— E. S. H. Awakened from sleep. Time, as 

 nearly as could be ascertained, 4.46.50 a. m. — J. E. K. 



Measurement of the record made bj^ the Ewing seismograph gives 

 the following data: 



Extreme duration, 30 seconds. 



Greatest motion, north and south (double amxalitude), 1.3 milli- 

 meters (magnified). 



Motion east and west, a little less. 



Vertical motion very small. 



Period of wave := about 0.3 second. 



Computed intensity = 88 = (IV -|-). 



The duplex pendulum seismograph gave a record in close agreement 

 with the above. 



