SCIENCE 



Editoeial Committee : S. Newoomb, Mathematics ; R. S. Woodward, Mechanics ; E. C. Pickbeing ; 



Astronomy; T. C. Mendenhall, Physics; R. H. Thurston, Engineering; Ira Remsen, Chemistry; 



J. Lb Contb, Geology; W. M. Davis, Physiography; Henry F. Osboen, Paleontology ; W. K. 



Beooks, C. Hart Mbrriam, Zoology; S. H. Soudder, Entomology; C. E. Bessey, N. L. 



Beitton, Botany; C. S. MiNOT, Embryology, Histology; H. P. Bowditch, Physiology; 



J. S. Billings, Hygiene; J. MoKekn Cattell, Psychology; 



J. W. Powell, Anthropology. 



Friday, February 9, 1900. 



CONTENTS: 



On ike Absorption of Condensation-producing Atmos- 

 pheric Dust by Solid Nuclei and Surfaces, and on 

 the Diffusion Velocity of supposedly Non-ionized 

 Dust Particles : PROFESSOR C ARL B ARUS 201 



Recent Outloohs upon Music : Charles K. Wead.. 206 



The Effect of the Mexican Earthquake of January 

 19th, at Mount Hamilton, Calif. : Professor R. 

 H. Tucker, J. E. K •. 215 



T%e Chicago Section of the American Mathematical 

 Society: Professor Thomas F. Holgate 218 



Cordilleran Sectio7i of the Geological Society of 

 America : Professor Andrew C. Lawson.... 219 



Prof essor Henry Allen Hazen : C. A 222 



Scientific Books : — 

 Annual Report of the Bureau of Steam Engineer- 

 ing of the Navy Department : R. H, T. Duck- 

 wall on Bacteriology. Books Received 223 



Scientific Journals and Articles 227 



Societies and A cademies : — 



Tlie Philosophical Society of Washington : E. D. 

 Preston. Geological Society of Washington : 

 F. L. Eansome, David White. Section of 

 Geology and Minefralogy of the New Yoj'k Acad- 

 emy of Sciences : Dr. Alexis A. Julien. Onon- 

 daga Academy of Science: H. W. Britcher. 

 Texas Academy of Science: F. W. S 227 



Discussion and Correspondence : — 



False Bibliographic Indications : F. A. Bather. 

 Fossil-hunting in Wyoming: Elmer S. RiGGS.. 231 



Current Notes on Physiography : — 

 Physiography of Jamaica; Nicaragua Canal 

 Route ; The Plains of Russia ; The Amalfl Land- 

 slip : Professor W. M. Davis '. 234 



Current Notes on 3Ieteorology : — 

 A Noteworthy Balloon Voyage; The Bagnios of 

 the Philippine Islands ; The Drought in India : 

 R. Dec. Ward 235 



Wagner Free Institute of Science 236 



Scientific Notes and News 237 



University and Educational News 240 



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

 for review sliould be sent to the responsible editor, Profes- 

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



ON TEE ABSORPTION OF CONDENSATION- 

 PRODUCING ATMOSPHERIC DUST BY 

 SOLID NUCLEI AND SURFACES, AND 

 ON THE DIFFUSION VELOCITY OF 

 SUPPOSEDLY NON-IONIZED 

 DUST PARTICLES.* 

 Let r be the radius of a tube stretched 

 along the axis X, and conveying dust-laden 

 air at a velocity, v. Consider two sections 

 at a distance dx apart; the dust entering 

 per second at the near face is nr'nv ; the 

 dust leaving per second at the rear face is 

 -r^(?i + [dn/dx]dx)v, if the air current is 

 kept constant and n is the density of dust 

 distribution, or is proportional to the num- 

 ber of particles per cubic centim. On the 

 other hand, the absorption of dust particles 

 by the walls of the section in question, is 

 k ■ 27rr ■ n ■ dx, where k is the absorption per 

 square centim. per second, per unit of dust 

 concentration, and the absorption, as a first 

 hypothesis, is taken proportional to the 

 density of distribution of particles in air.f 

 Hence — r.r'{dnldx')dx ■ v = h- 2xr ■ n ■ dx, 



dn 2k 

 or — = dx. (1) 



n vr 



Let the density in case of air saturated 



* Preliminary report ot work made with a grant of 

 the Smithsonian Institution, and published by per- 

 mission of the Secretary. 



t Briefly k is the diSusion velocity of the dust par- 

 ticle, i. e., its normal velocity in air at rest. Equa- 

 tion ( 1 ) neglects the spontaneous dissipation of dust 

 particles. This is permissible for the fast air currents 

 V ot Table I. The full equation is treated below. 



