360 



SCIENCE. 



[N. S. Vol. V. No. 113. 



combination of 40-incli focal length was used by 

 reversing the lens and putting the flint and 

 crown about 1 mm. apart. A number of views 

 were shown to illustrate the advantages of such 

 lenses. 



Several pictures were taken with an ordinaz-y 

 spectacle lens, 34-inch focus, stopped to about 

 -J-inch diameter, which were very good indeed 

 and scarcely distinguishable from those taken 

 with the telescopic lens or a telephotic com- 

 bination. Such a lens can be bought for ten 

 cents. 



J. F. Kemp spoke of the comparative useless- 

 ness of ordinary photographs in the study of 

 mountain geology, and believed that such a 

 simple camera would be of great value in field 

 work. The paper was discussed by others. 

 Wm. Hallock, 

 Secretary of Section. 



NEW YORE ACADEMY OF SCIENCES — SECTION OP 

 GEOLOGY, FEBEUAEY 15, 1897. 



The first paper of the evening was by Mr. F. 

 C. Nicholas, and was entitled ' Explorations in 

 iu the Gold Fields of Western Colombia.' Mr. 

 Nicholas described the curious placers in western 

 Colombia, which, while extremely rich in lim- 

 ited portions, are of very low grade when con- 

 sidered as extended propositions. The gold 

 gravels occur along the western base of the 

 Andes Mountains, and extend from the Gulf 

 of Darien southward, up the Atrato River, to 

 Quibdo. They are also found to the southward 

 of the San Juan River and are in the form of 

 terraces similar to the terraces of the Atlantic 

 States. After the formation of the auriferous 

 gravels the speaker supported the view that 

 igneous intrusions and upheavels had cut 

 them off from their parent hills in the interior 

 and had recognized the drainage, so that 

 the streams do not now head in auriferous 

 rocks. The surface geology indicated that the 

 Gulf of Darien formerly extended a long dis- 

 tance up the valley of the Atrato. Quite de- 

 tailed descriptions of the gravels and of the 

 character of the terraces were given in the 

 paper. Mr. Nicholas described a route by 

 which a man could sail in a canoe from the At- 

 lantic to the Pacific in the wet season by going 

 up the Atrato River to the Quito River, thence 



to the divide, which is in a series of swamps, 

 thence into the San Pablo River and on down 

 the San Juan to the Pacific. 



The second paper of the evening was by 

 Professor R. E. Dodge, entitled ' Recent Work 

 in Physiography.' 



Professor Dodge gave an outline of De Lap- 

 parent's 'Legons en Geographic Physique,' of Sir 

 John Lubbock's 'Scenery of Switzerland,' and 

 of two recent papers, one by M. R. Campbell, 

 entitled ' Drainage Modifications and their In- 

 terpretation,' and the other by C. F. Marbutt, 

 ' On the Physical Features of Missouri.' 



The last paper of the evening was by A. A. 

 Julien, on the - ' Sculpture and Sorting of 

 Sands.' The speaker, by means of lantern 

 slides, illustrated various varieties of sand and 

 their chief methods of origin and their compo- 

 sition. After citing the schemes for the classi- 

 fication of sands advanced by Zirkel and Dau- 

 bree he gave one of his own which was more 

 elaborate and was partly based on the method 

 of origin and partly on the physical characters. 

 J. F. Kemp, 

 Secretary. 



AMERICAN CHEMICAL SOCIETY — NEW YORK 

 SECTION. 



The meeting was held at the College of the 

 City of New York on Friday, February 5th, at 

 8:30 p. m.. Dr. Wm. McMurtrie presiding, and 

 about fifty members present. 



The first hour was occupied with the ' Dis- 

 cussion of the Relations of the Section with 

 the Scientific Alliance.' 



Professor Breneman opened the discussion. 

 Dr. Wiley described the work done by the 

 Affiliated Societies of Washington, the advan- 

 tages resulting from cooperation and more 

 which might result from a little additional 

 eifort. He stated that, with possibly one excep- 

 tion, the Washington Societies were all strictly 

 professional. 



Professors Sabin, Doremus and others spoke 

 strongly in favor of the Alliance ; others 

 thought the promised advantages had not ma- 

 terialized and that the returns were not pro- 

 portionate to the annual subscription. 



Dr. H. W. Wiley read a paper on the ' Value 

 of Foods and the Methods of Ascertaining it,' 



