SCIENCE 



Editoeial Committee : S. Newcoblb, Mathematics ; R. S. Woodward, Mechanics ; E. C. Pickering, As- 

 tronomy ; T. C. Mendenhall, Physics ; E. H. Thurston, Engineering ; Ira Eemsen, Chemistry ; 

 J. Le Conte, Geology; W. M. Davis, Physiography; O. C. Marsh, Paleontology; W. K. Brooks, 

 Invertebrate Zoology ; C. Hart Mbrriam, Vertebrate Zoology ; S. H. Scudder, Entomology ; 

 N. L. Brition, Botany ; Henry F. Osborn, General Biology ; H. P. Bowditch, 

 Physiology ; J. S. Billings, Hygiene ; J. MoKeen Cattell, Psychology ; 

 Daniel G. Brinton, J. W. Powell, Anthropology ; 

 G. Brown GtOODE, Scientific Organization. 



Fbiday, March 6, 1896. 



CONTENTS: 



Bemarks on the Progress of Celestial Sleclmnics since 

 the Middle of the Century: G. W. Hill 333 



Admission of American Students to the French Uni- 

 versities : G. Brown GooDE 341 



Application of the X-Eays to Surgery : Henry W. 

 Cattell 344 



Current Problems in Plant SlorpJwlogy : — 



On Some Characters of Floral Galls : Conway 

 MacMillan 346 



Current Notes on Anthropology : — 



The Wall Paintings of Mitla; Commerce across 

 Bering Straits; The Society of Americanists of 

 Paris: D. G. Beinton 349 



Scientific Notes and News : — 



A Director in Chief of Scientific Bureaus in the 

 Department of Agriculture ; Bontgen Bays and the 

 Boyal Society ; Astronomy: General 350 



Discussion and Correspondence : — 



Certitudes and Illusions : JosiAH RoYCB. Prof 

 C. Lloyd 3Iorgan on Instinct : "Wesley Mills. 

 The Chance of Observing the Total Solar Eclipse in 

 Norioay : A. LAWRENCE RoTCH. The Bontgen 

 Bays : Ralph R. Lawrence. Bontgen Bays 

 Present in Sunlight : CHARLES S. DoLLEY', Sen- 

 eca Egbert. Bontgen Bays from the Electric 

 Arc: W. S. Feanklin 354 



Scientific Literature : — 



Ortmann's Grundziige der Marinen Tiergeographie : 

 G. Baue. Cooke's Introduction to the Study of 

 Fungi: BYRON D. Halsted. The Geology of South 

 Dakota : C. S. Prosser. Lippniann's Chemie der 

 Zuckerarten: Ferdinand G. Weichmann 359 



Scientific Journals : — 



The American Journal of Science ; A merican Chem- 

 ical Journal : J. Elliott Gilpin. Psyche 370 



Societies and Academies : — 



Geological Section of the New York Academy of 

 Sciences : J. F. Kemp. The Torrey Botanical 

 Club : H. H. Eusby. Boston Society of Natural 

 History: SAMUEL Henshaw. Philadelphia 

 Academy of Natural Sciences : Edw. J. NOLAN. 

 Geological Society of Washington : W. F. MOR- 

 SELL. Geological Conference of Harvard Univer- 

 sity : T. A. Jaggar, Je. The Academy of 

 Science of St. Louis: Wm. Teelease. T!w 

 Woman's Anthropological Society : A. Carman. .372 



New Books 376 



BEMABKS ON THE PBOGBESS OF CELESTIAL 



MECHANICS SINCE THE MIDDLE OF 



THE CENTUBY* 



The application of mathematics to the 

 solution of the problems presented by the 

 motion of the heavenly bodies has had a 

 larger degree of success than the same ap- 

 plication in the case of the other depart- 

 ments of physics. This is probably due to 

 two causes. The principal objects to be 

 treated in the former case are visible every 

 clear night, consequently the questions con- 

 nected with them received earlier attention; 

 while, in the latter case, the phenomena to 

 be discussed must ofttimes be produced by 

 artificial means in the laboratory ; and the 

 discovery of certain classes of them, as, for 

 instance, the property of magnetism, may 

 justly be attributed to accident. A second 

 cause is undoubtedly to be found in the 

 fact that the application of quantitative 

 reasoning to what is usually denominated 

 as physics generally leads to a more difficult 

 department of mathematics than in the case 

 of the motion of the heavenly bodies. In 

 the latter we have but one independent 

 variable, the time; while in the former gen- 

 erally several are present, which makes the 

 difference of having to integrate ordinary 

 differential equations or those which are 

 partial. Thus it happens that, while the 



*Presidential address delivered before the American 

 Mathematical Society, December 27, 1895, by Dr 

 G. W. Hill. 



