RECORDS. 331 



locality very similar to the above in character, and afforded like 

 results. (3) Of several dark colored sphalerites some showed 

 a little light at the point of contact of the brush, 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 corundum wheel.) Xo 

 light from brushes (except 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 internal 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 Rock, Utah. Feeble greenish-blue 

 but similarly long trail. Duration over 0.08 s. 



6. Willemite. (i) Hard yellow-green gem material, Frank- 

 lin, N. J. Short greenish-yellow trail. Duration very short. 

 (2) Opaque, massive green variety. Feeble short green trail. 

 Duration about 0.02 s. Best obtained with a specimen 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. (i) Violet from Trumbull, Conn. Bright 

 green and very long trail ; best obtained by friction of a speci- 

 men 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) Red from Haddam Neck, Conn. Trail 

 similar. 



In the discussions that followed the papers. Dr. George F. 

 Kunz stated that Professor Baskerville and himself had under 



