May 27, 1904.] 



SCIENCE. 



827 



at the point of contact of the hrush, but no 

 trail. 



2. Quartz. (Sandpaper disc or grindstone.) 

 No light from brushes (except incandescent 

 sparks from hard steel). A piece of quartz, 

 however, gives a bright yellow light, and if of 

 rock crystal is luminous within by internal 

 reflection. Very short trail and duration. 



3. Corundum. (Emery paper disc or co- 

 rundum wheel.) No light from brushes (ex- 

 cept as above). A piece of ruby or ruby 

 corundum against the corundum wheel or a 

 grindstone evokes a brilliant crimson light 

 and short trail and is luminous within by in- 

 ternal reflection. Duration about 0.005 s. ; a 

 piece of emery against a corundum wheel 

 gives a like trail but is not itself luminous. 



4. Pectolite, Woodcliff, N. J. Wire brush. 

 Light greenish-blue trail only medium bright 

 but extending completely around the disc. 

 Duration over 0.08 s. 



5. Limestone, Hellfire Eoek, Utah. Feeble 

 greenish-blue but similarly long trail. Dura- 

 tion over 0.08 s. 



6. Willemite. (1) Hard yellow-green gem 

 material, Franklin, N. J. Short greenish- 

 yellow trail. Duration very short. (2) 

 Opaque, massive green variety. Feeble short 

 green trail. Duration about 0.02 s. Best ob- 

 tained with a spectrum pressed against a 

 corundum wheel or grindstone. Various 

 specimens give somewhat different effects. 

 (3) Pink or brown variety. Longer and 

 brighter green trail. Duration about 0.03 s. 



7. Chlorophane. (1) Violet from Trum- 

 bull, Conn. Bright green and very long trail; 

 best obtained by friction of a specimen against 

 a grindstone or corundum wheel or a disc 

 coated with the same material. Duration over 

 0.40 s. Spectrum broad band in the yellow- 

 green and green. (2) Green from Amelia Co. 

 Courthouse, Va. Trail similar but brighter; 

 spectrum similar. (3) Eed from Haddan 

 Neck, Conn. Trail similar. 



In the discussion of the paper that followed 

 Dr. George F. Kunz stated that Professor 

 Baskerville and himself had under examina- 

 tion a zinc-blende from Utah, the natural 

 mineral varying in color from yellow 



to fawn and to pale brown. This was the 

 most intense tribo-luminescent substance that 

 they had yet investigated. Two bits one 

 fourth the size of a pea, if pressed together 

 lightly with the fingers, caused a brilliant yel- 

 lew green light to glow as long as the pressure 

 lasted; and it also possessed the property of 

 becoming radio-responsive to the ' beta and 

 gamma rays of radium; that it was the first 

 natural zinc-blende they had examined that 

 showed this remarkable property. 



Mr. W. J. Hammer showed a sample of 

 artificial blende made by Mr. W. S. Andrews, 

 of Schenectady, N. Y., which gave very strong 

 tribo-luminescence. 



C. C. Trowbridge, 



Secretary. 



THE ACADEMY OP SCIENCE AND ART OF PITTSBURG. 

 SECTION OP BIOLOGY. 



The regular monthly meeting of the sec- 

 tion was held on February 2 in the lecture hall 

 of the Carnegie Institute. Three topics were 

 presented. The first paper was offered by Mr. 

 W. E. Clyde Todd, on 'The Birds of Erie 

 and Presque Isle, Erie County, Pa.' This 

 paper is based on his personal observations 

 during the season of 1900, supplemented by 

 extensive field notes made by local observers, 

 and published records. 



The locality in question is considered by 

 the author as the most favorable in the entire 

 state for the study of water-birds. Two hun- 

 dred and thirty-seven species are recorded. A 

 full account is given of the physical features 

 and climatic conditions of the lake shore 

 plain, and after a careful study of the avi- 

 fauna of the region Mr. Todd reaches the 

 conclusion that it should be included in the 

 AUeghenian fauna. 



Dr. A. E. Ortmann followed with a paper on 

 ' The Cosmopolitan Character of the Deep-Sea 

 Fauna,' stating that a small collection of deep- 

 sea schizopods from the Hawaiian Islands, 

 recently received at the Carnegie Museum, has 

 furnished a few new cases which show very 

 wide horizontal distribution. Species found 

 hitherto only in the Atlantic Ocean are re- 

 corded for the first time from the Pacific, a 

 circumstance which strongly suggests their 



