76 . Scientific Intelligence. 



were altogether wanting, and the groups of dark lines A, B and 

 a which M. Janssen had previously found to vary as the simple 

 density, were so much enfeebled as to leave little doubt that they 

 too would disappear, could we entirely eliminate the effects of 

 the earth's atmosphere. — Nature, Nov. 8, 1888, p. 40. j. t. 



9. Effect of staining upon dry plates. — "At the meeting of the 

 Physical Society of Berlin, Nov. 2, Professor Kundt exhibited a 

 number of photographs of spectra photographed upon dry plates 

 which had been stained with various substances. The plates 

 stained with chlorophyl gave especially interesting results. The 

 spectra obtained upon them consisted of a bright strip ending 

 near F followed by a dark portion intercepted by an extremely 

 bright line at the spot where the absorption band of chlorophyl is 

 present in the red. Plates stained with eosin similarly showed a 

 bright strip corresponding to the absorption band of this sub- 

 stance in the yellow, whose brightness was much greater than 

 that of the rest of the spectrum. These experiments showed that 

 the rays of light which are absorbed by the above coloring mat- 

 ter exert an extremely active chemical action on the plate. Ex- 

 periments made with a view to determining whether absorption 

 of light has a similar effect on fluorescence yielded negative 

 results. It still remains to investigate whether the maximum 

 brightness of the spectrum photographed on a plate stained with 

 chlorophyl corresponds exactly with the absorption found of this 

 substance, taking into account the influence of the solvent used 

 for the solution of the chlorophyl on the position of its absorption 

 band." — Nature, Nov. 29, 1888, p. 120. J. T. 



10. Electrical currents produced by light. — Stoletow employed 

 the following apparatus in his investigation upon this subject. 

 A glass cylinder is closed at one end by a quartz plate Avhich is 

 silvered in net form, though the other end of the cylinder passes 

 a micrometer screw terminating in a silvered iron plate. This 

 iron plate and the silver net work on the quartz plate served as 

 electrodes. The cylinder was filled with various gases which 

 were submitted to the rays from an electric light. No difference 

 could be perceived in the behavior of moist and dry air and 

 hydrogen at ordinary pressures. Carbonic acid, however, gave 

 double the effect of the above mentioned gases. With diminish- 

 ing pressures the effect increases until the pressure of 3-4 mm. is 

 reached and then diminishes. — Comptes Rendus, 107, 1888, pp. 

 91-92. j. T. 



II. Geology and Natural History. 



1.* Cambrian of Bristol County, in Eastern Massachusetts. — 

 Professor N. S. Shaleb has reported, in the Bulletin of the Mu- 

 seum of Comparative Geology of October, 1888 (vol. xvi, No. 2), 

 the discovery of Cambrian fossils near Attleborough, a few miles 

 from the northeast angle of Rhode Island, The region lies on 

 the west of the main belt of the Carboniferous of the Narragan- 

 sett basin. East of it is an area of gneiss, which is probably 



