December 18, 1903.] 



SCIENCE. 



7H9 



for right-handedness and Icft-handoihicss in 

 quite a different way. According to their be- 

 lief, Anjea, the mythological fashioner of 

 babies makes them all right-handed, but 

 Thunder (who really existed before Anjea and 

 made him) can also form infants and, when- 

 ever he makes any, they are all left-lianded. 



Al.EX.\NDER F. ClIAMBERLAIX. 



Clabk Umvehsity, 

 November 6, 1003. 



SOCIETIES AND ACADEMIES. 



NEW YORK ACADEMY OF SCIENCES. SECTION OF 



GEOLOGY AND MINEK.\LOGY". 



The regular meeting of the section was 

 held on Xovember 16 at the American Mu- 

 seum of Natural History. The first business 

 was the election of officers for the year 1904, 

 and Professor James F. Kemp was elected 

 chairman, and Dr. Edmund Otis Hovey, sec- 

 retary. 



The first paper of the evening was by Doctor 

 A. W. Grabau, of Columbia University, and 

 was entitled ' Discussion of and Suggestions 

 Regarding a Xew Classification of Rocks.' 

 The speaker said in part that all classification 

 ought, as far as possible, to be genetic or ac- 

 cording to progi-essive development. Such a 

 classification is practicable in the biologic 

 sciences, but not in those which, like miner- 

 alogy, deal with inorganic substances. In 

 developing his theme the speaker suggested 

 the following provisional subdivisions : Endo- 

 genetic rocks, or those formed by chemical 

 means, and e.xogenetic or clastic rocks, which 

 are chiefly of mechanical origin. The first 

 group was further subdivided into pyrogenic 

 or igneous rocks; hydrogen ic or aqueous 

 rocks; biogenic or organic rocks. The hydro- 

 genic and biogenic rocks were each again 

 subdivided into rocks of calcareous, silicious, 

 ferruginous, carbonaceous and miscellaneous 

 composition; and a further subdivision was 

 made into unaltered and altered or metamor- 

 phic types. 



The exogenic or clastic rocks were divided 

 into autoclastic, hydroclastic, pyroclastic, bio- 

 clastic and anenioclastic. 



A further subdivision according to texture 

 was into rudaceous or conglomeratic, arena- 



ceous or sandy, and lutaceous or mud rock. 



The next division was according to com- 

 position into two main groups, silicious and 

 calcareous, and finally into unconsolidated and 

 consolidated and metamorphic rocks. 



In the discussion of the paper Professor 

 Stevenson spoke of the value of such a classi- 

 fication through its giving to teachers ideas 

 for presentation to their classes regarding the 

 interrelations of rock. Professor Kemp spoke 

 of the system as being well adapted to geol- 

 ogic Study on account of its giving the sur- 

 roundings in which any specified rock has 

 developed, although it is not practicable to 

 assign a place to every small rock group which 

 is really of mineralogical rather than of geo- 

 logical value. 



The second paper of the evening was by 

 Wallace Goold Levison, ' Notes on Fluorescent 

 Gems.' The author said, in abstract: 



Fluorescence, or the property of reducing 

 the wave-length of certain luminous rays, en- 

 hances the beauty of a few colored gems under 

 conditions which lessen the effectiveness of 

 others that do not possess this property. 

 Garnet, for instance, which is non-fluorescent, 

 loses its rich crimson color and becomes dull 

 gray in pure blue light. On the contrary, 

 most kinds of ruby and ruby spinel and pink 

 topaz respond to light rays above the red on 

 account of their fluorescence, and in blue- 

 violet light still display their characteristic 

 tints. The red color of the ruby is somewhat 

 developed by the light of the air-gap spark 

 and an uncovered Crookes tube. It is in- 

 tensely e.\cited by the cathode rays. Willem- 

 ite displays a beautiful greenish-yellow color 

 not only in ordinary light rich in the yellow- 

 green rays, but also in light consisting chiefly 

 or wholly of the more refrangible colors in 

 which its characteristic color would be effaced 

 but for the possession of fluorescence in high 

 degree. This mineral is excited furthermore 

 by some of the ultra-violet rays and by the 

 Roentgen and Becquerel rays. 



Other materials which owe desirable tints to 

 fluorescence arc pearl, opal, hyalite, chalce- 

 dony and kunzite (the new lilac spodumene). 

 Iliddenito, the green spodumene, seems to be 

 non-fluorescent. Impaired by fluorescence are 



