788 



SCIENCE. 



[N. S. Vol. III. No. 73. 



■was descriptive of certain plates whicli were 

 exMbited appearing to indicate a magnetic ac- 

 tion on photographic plates. These are called 

 magnetographs and were made by placing vari- 

 ous objects directly on the photographic film 

 and suspending a magnet in front of them. No 

 satisfactory explanation or theory of the results 

 has been given. Fifth note : In conclusion, 

 Mr. Leviston pointed out certain causes which, 

 in his opinion, might account for the deteriora- 

 tion of photographic plates, suggesting among 

 other things X-rays from unexpected sources, 

 terrestrial magnetism, plant or fungus organ- 

 isms, and gases, such as sulphuretted hydrogen, 

 penetrating the boxes and injuring the plates. 

 He suggested that the test should be made by 

 enclosing the plates in soldered metal boxes. 

 These notes were discussed by Profs. Mayer, 

 Hallock, Van Nardroff, and others. 



By permission of the Section Mr. C. C. Trow- 

 bridge read a paper entitled ' The Use of the 

 Hair Hygrometer, ' which will be published in 

 this Journal. W. Hallock, 



Secretary of Section. 



ACADEMY OF NATURAL SCIENCES OF PHILA- 

 DELPHIA, APRIL 14. 



In connection with the presentation of a col- 

 lection of recent and fossil Strombida Mr. H. 

 A. Pilsbry discussed the ancestry of Strombus 

 Oostata and Melongena subcoronata, their rela- 

 tions, fossil species being illustrated by large 

 suites of intermediate forms. 



Mr. Jos. Willcox commented on the influence 

 of environment on the species as illustrated by 

 specimens presented. It was apparent that 

 those from the southern coasts of Florida swept 

 by the Gulf Stream were all of a dwarfed type. 



Mr. Benj. Sharp related the plentiful occur- 

 rence of a tetenophore, Mneopsis Ludyi in a 

 fresh water pond near Nantucket. The em- 

 bryos had been swept in by an accession of salt 

 water and had accustomed themselves to their 

 new environment. The species did not, how- 

 ever, persist in the pond in consequence prob- 

 ably of the severity of the winter. Speci- 

 mens of the species referred to were beautifully 

 preserved in a two per cent, solution of forma- 

 line. 



Mr. Pilsbry announced the finding, by Mr. 



Chas. Johnson, for the first time, in the Eocene 

 of Texas, of a representative of the genus seal pil- 

 lum. It is a new species for which the name 

 Chamberlaini was proposed, in recognition of 

 the services of the Rev. Dr. L. T. Chamber- 

 lain to paleontological science. 



Edw. J. Nolan, 



Recording Secretary. 



NORTHWESTERN UNIVERSITY SCIENCE CLUB, 

 APRIL 3. 



Dr. Marcy in chair. Prof. G. W. Hough pre- 

 sented the topic, ' Instruments for Recording 

 the Time of Astronomical Observations.' He 

 described various steps in the use of electric 

 clock signals and the methods of mechanical re- 

 cord of such signals. After explaining a num- 

 ber of contrivances for securing uniform circulai"^ 

 motion he described his printing chronograph, 

 which prints with type the minutes, seconds, 

 and hundredths of seconds of the time of the 

 observation. The instrument has been in use 

 since 1871, is easily kept in order, and has a 

 great advantage over the recording chrono- 

 graph in saving labor in meridian observations. 



In the discussion Prof Crew described de- 

 vices used in securing uniform circular motion for 

 chronographs at Johns Hopkins and at Lick 

 Observatory. A. R. Crook, 



Secretary. 



EvANSTON, III. 



NEW BOOKS. 



Electric Lighting. Volume I. The Generating 

 Plant : Francis B. ("rocker. New York, 

 D. Van Nostrand Co.; London, E. and F. 

 N. Spon. 1896. Pp. viii-f444. 



Mathematical Papers read at the International 



■ Mathematical Congress. Edited by E. Hast- 

 ings Moore, Oskar Bolza, Heinrich 

 Maschke, Henry S. White. New York, 

 Macmillan & Co. , for the American Mathe- 

 matical Society. 1896. Pp. xvi+411. $4.00. 



Wages and Capital. F. "W. Taussig. New 

 York, D. Appleton & Co. 1896. Pp. xviii 

 -1-325. 



Buhmkorff Induction-Coils. H. S. MoRRiE. New 

 York, Spon and Chamberlain. 1896. Pp. 

 xviii+183. 



