SCIENCE 



Editorial Committee : S. Newcomb, Mathematics ; E. S. Woodwaed, Mechanics ; E. C. Pickeeing, 



Astronomy; T. C. Mendenhall, Physics; E. H. Thurston, Engineering; Iea Eemsen, Chemistry; 



J. Le Conte, Geology; W. M. Davis, Physiography; O. C. Maesh, Paleontology; W. K. Beooks, 



C. Haet Meekiam, Zoology; S. H. Scuddee, Entomology; C. E. Bessey, N. L. Beittost, 



Botany; Heney F. Osboen, General Biology; C. S. Mikot, Embryology, Histology; 



H. P. BowDiTCH, Physiology; J. S. Billings, Hygiene ; J. McKeen Cattell, 



Psychology; Daniel G. Bbinton, J. W. Powell, Anthropology. 



Friday, July 1, 1898. 



CONTENTS: 



A New Constituent of Atmospheric Air: Peofes- 

 soE William Eamsay 1 



Liquid Hydrogen : — 



Preliminary Note on the Liquefaction of Hydrogen 

 and Helium ; The Boiling Point and Density of 

 Liquid Hydrogen : Peofessoe James Dewae.. 3 



The Specific Heat of dietals at Low Temperatures : 

 C. C. Teowbeidge , 6 



The Flicker Photometer : Peofessoe Feank P. 

 Whitman ; 11 



Biological Survey of Lake Erie: H. M. Smith 13 



Eugene Flachat : E. H. T 14 



Current Notes on Bleteorology : — 



31ohn's Grundziige der 31eteorologie ; Van Beb- 

 ber's Weltervorhersage : The Climate of Cuba : 

 e: Dec. Waed 15 



Current Notes on Anthropology : — 



The Building Sacrifice ; The Custom of Dharna : 

 Peofessoe D. G. Beinton 16 



Scientific Notes and News : — 



Meeting of the American Association ; Award of the 

 Loubat Prizes ; New Gases in the Atmosphere ; The 

 Civil Service Examinations in Science ; General 17 



University and Educational News 21 



Discussion and Correspondence : — 



On the Early Sense of Self : PEOFESSOE HiEAM 

 M. Stanley. Color Vision : C. Ladd Feank- 

 LIN 22 



Scientific Literature: — 



Goebel's Organographie der Pflanzen : PEOFES- 

 SOE Conway MacMillan. Sanford's Course 

 in Experimental Psychology : De. E. W. Sceip- 

 tuee 23 



Scientific Journals 25 



Societies and Academies: — 



The Philadelphia Academy of Natural Sciences: 

 De. E. J. Nolan. Tlie Chemical Society of 

 Washington: William A. Keug 26 



New Books 28 



MSS. intended for publication and books, etc., intended 

 for review should be sent to the responsible editor. Profes- 

 sor J. McKeen Cattell, Garrison-on-Hudson, N. Y. 



ON A NEW CONSTITUENT OF ATMOSPHERIC 

 AIR* 



This preliminary note is intended to give 

 a very brief account of experiments which 

 have been carried out during the past year 

 to ascertain whether, in addition to nitro- 

 gen, oxygen and argon, there are any gases 

 in air which have escaped observation ow- 

 ing to their being present in very minute 

 quantity. In collaboration with Miss 

 Emily Aston we have found that the nitride 

 of magnesium, resulting from the absorp- 

 tion of nitrogen from atmospheric air, on 

 treatment with water yields only a trace of 

 gas ; that gas is hydrogen, and arises from 

 a small quantity of metallic magnesium un- 

 converted into nitride. That the ammonia 

 produced on treatment with water is pure 

 has already been proved by the fact that 

 Lord Rayleigh found that the nitrogen pro- 

 duced from it had the normal density. 

 The magnesia, resulting from the nitride, 

 yields only a trace of soluble matter to 

 water, and that consists wholly of hydrox- 

 ide and carbonate. So far, then, the re- 

 sults have been negative. 



Recently, however, owing to the kindness 

 of Dr. Hampson, we have been furnished 

 with about 750 cubic centimeters of liquid 

 air, and, on allowing all but 10 cubic centi- 

 meters to evaporate away slowly, and, col- 



*Paper read before the Royal Society on ,Tune 9th 

 by Prof essor William Eamsay, F. E S., and Morris 

 W. Travers. Eeceived by the Society June 3d. Re- 

 printed from Nature. 



