108 [June, 



June 2Qth. 



Vice*President Bridges in the Chair. 



The Committee on Dr. Owen^s paper on a new Mineral from Califor- 

 nia, reported in favor of publication : 



Notice of a New Mineral from California. 

 By D. D.Owen, M.D. 



Mr. Henry Pratten, one of my assistants in the geological surveys in the 

 North West in 1848 and 1849, went to California in the spring of 1850, and 

 returned last February. Being interested in mineralogy and geology, he made 

 observations in these departments of science, both on his way out and during the 

 time he remained there. 



The mineral in question he obtained at a locality known as the Wisconsin 

 and Illinois claim, near Nevada City, at which place he resided most of the 

 time he remained in California. 



At the time he collected this mineral it struck him as something remarkable 

 and different from anything he had previously observed ; and he made at the 

 time some experiments on its blowpipe reactions, without being able positively 

 to decide what it might be. 



He then first submitted it to a distinguished mineralogist, who referred it to 

 the species Karpholite. 



In comparing its blowpipe reactions with that mineral, Mr. Pratten doubted 

 the correctness of the conclusion that it belonged to the species Karpholite, and 

 so did Dr. Norwood, who also examined its blowpipe reactions ; and they came 

 to the conclusion that its indications before the blowpipe resembled more those 

 of Molybdic acid. 



When I returned home last March, Mr. Pratten submitted it to me and I made 

 a qualitative examination of the mineral in the humid way, and ascertained, 

 from the reactions of the solution of the mineral with sulphuretted hydrogen, 

 iodide of potassium, and ferro-cyanide of potassium, that the principal consti- 

 tuents were molybdenum and iron. 



I found, moreover, that it was easily acted on by liquid ammonia, the molyb- 

 denum being dissolved, while oxide of iron was set free in brownish red flocks. 



These chemical reactions proved that though the mineral resembles Karpho- 

 lite in the yellow color of its fibrous, acicular, tufted crystals, it is quite 

 different in its chemical constitution. 



I made, also, an approximate quantitative analysis on a centigramme of the 

 mineral, which was all that could be spared at that time, by solution in liquid 

 ammonia ; collecting the precipitated iron on a filter, washing and weighing it 

 after ignition. The molybdenum was then separated by sulphuretted hydrogen. 



The solution freed from molybdenum was evaporated with addition of hydro- 

 chloric acid to free the solution of HS ; after filtration it was evaporated to 

 dryness and ignited, and the small percentage of alkali and magnesia weighed 

 together; the magnesia, after being separated by peroxide of mercury, was 

 Weighed by itself. 



The result of the analysis gave : 



H=Water 15 



Mo (?) Molybdic acid(?) . . 40 compound of molybdenum and oxygen 

 Fe Peroxide of iron . . .35 



Alkali 9 



Mg Magnesia .... 2 



That the molybdenum exists in this mineral as molybdic acid is altogether 

 probable from the fact of liquid amiBinia acting on it so readily. 



