THE WEST AMEEICAN SCIENTIST. 31 



SAN FRANCISCO MICROSCOPICAL SOCIETY. 



The current issues of the principal scientific periodicals were added to the files, 

 and William Norris donated a pamphlet, by Warren and Chase, descriptive of over 

 twenty new and rare diatoms, and containing photographic illustrations of the 



Honorary membership was conferred upon Dr. Henry Ferrer of this city. Dr. 

 F. Riehl of Alameda was elected a resident member. 



Ihe committee having in charge the preparation of a revised edition of the 

 Society's constitution was instructed to proceed with the printing thereof. 



A slide of Spirogyra crassa, in fruit, was handed in by Mr. Breckenfeld, who 

 stated that Dr. Cooke, in his recently-published work on Fresh-water Algae, gave 

 .16 mm. as the largest recorded diameter of the filaments of this interesting s ecies 

 — the largest of its genus. But in the slide under consideration, careful measure- 

 ments showed the average diameter of the filaments to be 1-150 of an inch (equal to 

 .17 mm.), while in many cases the diameter exceeded .18 mm. Ihe California 

 variety was therefore the largest in the world, owing probably to * our glorious cli- 

 mate. ' Th'e plant was found growing in a ditch near Napa. 



Under a Spencer dry, ^-inch objective, of 115*^ angle, were shown specimens of 

 the exquisite diatom, Cestodiscus superbus, and also the striae, or marking on the 

 valves of No. 18, on Holler's ' Probe-Platte ' of diatoms, mounted in phosphorus. 

 The latter diatom was also shown. 



The ' Improved Beck Microscope Lamp,' just received by Dr. Selfridge, was 

 exhibited by him to the members present. 



A number of objects were splendidly shown by Dr. Stallard. 



A. H. Breckenfeld, Rec. Sec'y. 



A new theory of the formation of coal has been propounded by Mons. L. 

 Breton, who considers it to have been produced by the sinking of floating islands 

 like those which now occur on many lakes and rivers, and which are especially 

 noticeable on the Upper Nile. The turf of which these islands are chiefly com- 

 posed becomes fossilized at the bottom of the water. 



The common perfumes used in confectionery and cordials have been investigated 

 by two French chemists. Large quantities of these chemicals proved poisonous 

 to animals, but it is doubtful whether the quantities actually employed by the con- 

 fectioners or liquor manufacturers are considerable enough to do harm. 



Not a single instance of color-blindness has been found by Schwarzbach in an 

 examination of 2000 Hottentots, Malays, Melanesians, Australians, Mao.i. and 

 Polynesians; and he concludes that the defect is confined to the white race, and is 

 due to influences connected with civilized life. 



The beautiful red plumage of a South African species of birds has been chem- 

 ically examined and found to be due to copper. When the birds are kept from food 

 containing copper they entirely lose the tint produced by tlmt mineral. 



