76 Scientific Intelligence. 



the Academy represent faithfully some object sufficiently diverse, 

 a stained glass window of four colors, red, green, blue, yellow: 

 a group of draperies; a plate of oranges, surmounted by a red 

 poppy; a many-colored parrot. These show that the shape is 

 represented simultaneously with the coloi-6. The draperies and 

 the bird required from five to ten minutes' exposure to the electric 

 light or the sun. The other objects were obtained after many 

 hours of exposure to a diffuse light. The green of the foliage, 

 the gray of the stone of a building are perfectly reproduced on 

 another cliche. The blue of the sky, on the contrary, was repre- 

 sented as indigo. It remains then to perfect the orthochromatism 

 of the plate, and to increase considerably its sensitiveness." — 

 Nature, May 5, 1892. j. t. 



9. Dispersion of the Ultra Red Mays. — At a meeting of the 

 Physical Society in Berlin, March 1.1, Dr. Rubens discussed this 

 subject. He had extended his observations from wave-length 

 S'Yyu to wave-length SyU. The curves representing changes in 

 index of refraction do not agree with Professor Langley's views 

 on this subject. To wave-length o'3/.t Rubens's curves coincide 

 with those of Langley. But beyond this point the interpolations 

 of Professor Langley do not agree with Rubens' s observations. 



J. T. 



10. Electrical Resistance of the Human Body. — The frequent 

 controversies which have taken place upon this subject, especially 

 in relation to accidents from electrical currents, make a late paper 

 by M. von Fret (Verh. d. X. Congr. f. innere Medizin, Wies- 

 baden, 1891, p. 377) of considerable interest. The author em- 

 ployed Kohlrausoh's method of determination of the electrical 

 resistance of electolytes. The metric length in Kohlrausch's ap- 

 paratus was supplanted by a circularly formed channel, the ends 

 of which were not joined. This channel was filled with a sul- 

 phate of zinc solution. The conducting electrodes were greatly 

 increased in size over those employed by Kohlrausch. With 

 large electrodes suitably proportioned to the extent of surface of 

 the wet hands, the resistance of the body from hand to hand was 

 found to be small, 300 to 400 ohms. The author discusses the re- 

 lation between the size of electrode and the resistance of the 

 human skin. According to him the seat of the electric polariza- 

 tion of the body is in the outer surface and layers of the skin. — 

 Beibldtter Ann. der Physih und Chemie, No. 4, 1892, p. 217. 



J. T. 



II. Geology and Mineralogy. 



1. The History of Volcanic Action in the Area of the British 

 Isles, by Sir Archibald Geikie. Anniv. Address Geol. Soc. 

 London, Feb. 19, 1892. 120 pp. Svo. — This second part of Sir 

 Archibald Geikie's Memoir on volcanic action in the British 

 Islands treats of the evidences of such action and the volcanic 

 phenomena and rocks, in connection with the Old Red Sandstone; 



