164 PROCEEDINGS OF THE CALIFORNIA 



depth, the observer notes the reading of the galvanometer, which 

 readings are reduced to Fahrenheit degrees. 



Dr. Blake suggested that the unexposed end of the pile should 

 be surrounded by ice, and that by a non-conductor. 



Professor Davidson said the suggestion was a good one, and that 

 he was anxious to receive suggestions on that and any other point, 

 in order that he may arrive at some knowledge of the conditions of 

 sub-surface temperature, and their influence upon the ocean cur- 

 rents, etc. 



Regular Meeting, April 3rd, 1871. 

 President in the Chair. 



Donations to the Cabinet : Compounds of cinnabar, chrome and 

 asphaltum from New Almaden mines, by Mr. Durand. A species 

 of Libinia, also apples with a parasitic growth on the skin resem- 

 bling fungus spores, by Dr. H. Gibbons. 



Dr. Blake spoke of the earthquake shock last evening, which 

 seemed to vibrate from north to south. It was more severe at San 

 Jose, and across the Bay, than in this city. 



Dr. Ayres said that the severest shocks here were scarcely felt 

 in the direction of Clear Lake, beyond Mount St. Helena. 



Mr. Bloomer quoted from Brigham's history of earthquakes in 

 New England, from 1568 to 1870, that 148 occurred in winter, 

 and but 74 in summer. 



Mr. Heynemann thought that the changes in the weather and 

 wind yesterday were connected with the earthquake. He offered 

 the theory, that if a moist current of air is above, and a dry one 

 below it, a thunderstorm may be produced ; while the opposite 

 condition of currents, after a continued drought, may cause an 

 earthquake. 



Rev. F. Hanson having gone east. Dr. J. G. Cooper was elected 

 Corresponding Secretary, subject to the approval of the Board of 

 Trustees.' 



