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1 60 Proceedings of Societies, 



perfectly done, and when dealing with new species this is a matter 

 of considerable importance. In the geography of western botany, 

 the work of the department differs notably from that of the Harvard 

 Herbarium. This is especially apparent in generalizations, as upon 

 the plants of Guadalupe Island, where the list of the twenty -nine 

 species given as peculiar to the island embraces Trifohwn Palmeri, 

 Hosackia ornithopiis, Harpagonella Palmeri, Convolvulus Occident- 

 alls, Convolvuhis macrostegiics and Mimithts latifolms. 



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PROCEEDINGS OF SOCIETIES. 

 California Academy of Sciences. July 7, i8go. President Harkness in the 



chair. 



Mr. F. Gutzkow gave some interesting information regarding a diatomaceous earth 

 from Sonoma County. This mineral, which is found in many places in California, 

 consists chiefly of silica and water, and is of considerable economic importance. 

 It has been used for building; as a polisher under the name of electro-silicon; in 

 glass-making; and as an absorbent for nitro-glycerine in the manufacture of giant 

 powder, etc. That obtained in California, has unfortunately been found unfit for 

 the manufacture of giant powder and the presence of a small quantity of iron pre- 

 vents its being used for making white glass. Mr. Gutzkow stated that he had 

 devised a cheap and efficient method of eliminating the iron; the method depends 

 on the volatility of ferric chloride. 



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C. H. Eigcninann exhibited specimens of salmon, salmon trout and trout, explain- 

 ing that the individuals of a species differ so much according to the condition, the 

 season, the bottom over which they live and the sex, that it is sometimes almost | 



impossible for anyone but an ichthyologist to distinguish between species. This 

 had caused the trouble between the Fish Commissioners and the deputies, about 

 which so much was said a few months ago. A large number of specimens of Lake 

 Tahoc trout were exhibited, Mr Eigenmann having just returned from Donncr and 

 Tahoe, bringing all the variations of that species which were to be had at this time. 

 Much diversity of opinion exists among the Tahoe fishermen as to the number of 

 species of trout found in that region, all seeming to think that there are at least two 

 and some placing the number as high as six, namely, the big black trout, the red 

 trout, the porgy (or pogy), the silver trout, the yellow-belly and the brook trout. 

 With the possible exception of the first named, which Mr. Eigenmann did not see, 

 these "varieties" were conclusively shown to represent a single species, Salmo 

 purpiiratiis henshawi. 



July 21, iSgo. President Harkness in the chair. 



Mr. G. P Rixford exhibited specimens of marble from Inyo County, and carbon- 

 ate of soda from the soda works of Owens Lake, giving a description of the process 

 of manufacture. 



Dr. H. Carrington Holton called attention to the coming meeting of the Ameri- 

 can Association for the Advancement of Science, and explained the aims and 

 objects of the a.ssociation. 



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