GEOLOGY. 265 



gelatinous, or after havirg been dried and ground up with water, 

 never gives a plastic paste ; nor can water be the cause, since melted 

 glass and sealing-wax both possess the property. 



The author considered that the phenomenon may bo due to a 

 change in the molecular arrangement -of the particles of the clay and 

 the consequent variation of the attractive force which holds them 

 together, the particles under the circumstances under which clay is 

 plastic being nearer to one another, and the attractive, force conse- 

 quently greater, than under the circumstances when the clay has the 

 property of rigidity. 



As to the odor of clay, the author pointed out some difficulties in 

 the way of the common opinion that alumina is the cause of this 

 property, and suggested various considerations which might lead to 

 the elucidation of the point. 



QUICKSILVER MINES OF CALIFORNIA. 



The San Francisco Mining and Scientific Press says: " There 

 have been many recent discoveries of rich cinnabar in various por- 

 tions of our prolific State, in consequence of the long stoppage of the 

 great New Almaden Mine, owing to tedious and vexatious litigation. 

 This mine, however, is at last in full operation again, and its annual 

 product of over 1,000,000 pounds of quicksilver will again be in the 

 market. The New Almaden, New Idria, Enriquita, and Gaudaloupe 

 Mines of Santa Clara county, with the many recently-discovered and 

 only partially-worked cinnabar veins of Napa and Sonamo counties 

 (which contain liquid quicksilver), already turn out SOIIIG 4,000,000 

 pounds of quicksilver per annum, an amount nearly large enough 

 to supply the world, and, doubtless, when these latter shall have 

 been more thoroughly opened, the yield will reach the high figure of 

 8,000,000 pounds, the value of which, at the rate of 30 cents per 

 pound, would be no less than $2,400,000 ; and this we think is a mod- 

 erate estimate. Hittell sets the average aggregate annual yield of 

 the four great Santa Clara mines at 3,510,000 pounds, but it has 

 reached as high as 4,275,000 pounds ; and as they are by no means 

 worked to the best advantage, we may safely look for largely increased 

 returns as the operations of the companies are extended. Accounts 

 recently received from Washoe also speak of rich cinnabar veins dis- 

 covered. With so many mines and such vast yields, we may safely 

 predict that the wholesale price of quicksilver will constantly decrease 

 until it reaches eight or ten cents per pound. Quicksilver will then 

 be used with a more liberal hand in the search for gold and silver, 

 and many other advantages to the world will arise from its cheap- 

 ness. 



ECONOMIC EFFECTS OF THE RECENT GOLD DISCOVERIES. 



An interesting paper on the above subject was presented to the 

 British Association at its last meeting, 18G2, by Mr. Henry Fawcett. 

 Pie commenced by alluding to the confident predictions which were 

 made when the rich gold deposits of Australia and California first be- 

 came known, that the value of this metal would be rapidly and largely 

 depreciated. Governments were advised to change the standard of 

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