224 PROCEEDINGS OF THE CALIFORNIA 



forced up the smaller tube, if the column of glycerine did not partly 

 compensate for the loss of atmospheric pressure. In my experi- 

 ment, the mercurial column fell only half an inch, instead of one 

 inch, and the corresponding rise in the glycerine column was twelve 

 inches. To read off the rise and fall, I compared its readings with a 

 standard mercurial barometer, and graduated the inches on a very 

 large scale on the small tube. The instrument which I constructed 

 last May was very sensitive, and exhibited changes of the one-two- 

 hundredth of an inch very clearly, both for weather, and in ascend- 

 ing and descending a flight of stairs." 



Dr. Blake made some remarks in reference to the geology of a 

 portion of Napa county, recently visited by him, stating that he had 

 discovered another petrified forest at a much greater elevation than 

 the one previously known ; the trunks of some of the trees meas- 

 •urino; one hundred and fifteen feet in length ; the forest which he 

 had visited was in a northwesterly direction from the other ; the 

 surface for about one hundi-ed and fifty yards square, is covered 

 with petrified wood. 



Dr. Henry Gibbons remarked that several eminent scientists had 

 stated that there was an excessive amount of cerebral disease pre- 

 valent, and desired to know whether the electric condition of the 

 .atmosphere might not have some relation thereto. 



Eegdlar Meeting, (deferred to) June 5th, 1872. 

 President in the Chair. 



'Forty members present. 



Donations to the Library : Description of a gigantic Amphib- 

 ian, by G. Krefft, presented by Thomas Davidson. Eng. and Min- 

 ing Jour. R. Comitate Geologico D'ltalia, Nos. 5 and 6, 1872. 

 Contributions to the Icthyology of the Lesser Antilles. Am. 

 Chemist. Monatsbericht der Konigtichen Preus. Akad. der Wes- 

 senchaften zu Berhn. Overland Monthly. Ann. Report Trustees 

 INIus. Comp. Zoology of Cambridge, Mass. The Horticulturist, 

 Yol. I, No. 6. De I'emploi de I'Eau eu Cliirurgie, par Dr. AI- 



