26 



ASSOCIATIONS FOB THE ADVANCEMENT OP SCIENCE. (AMERICAN.) 



15-inch equatorial. The speaker rapidly sketched 

 the rise and progress of photography as applied to 

 the moon, the sun. and the heavens, much of the 

 work being done by American investigators. The 

 completion of Lick Observatory marked a decided 

 advance in study, since the large telescope there 

 favored the work. The Paris photographs of 

 Loewy and Puiseux, made with a special form of 

 telescope, excel anything that has yet been done, 

 however. Dr. Barnard followed the progress of 

 work on the sun, which at first sought detail on the 

 surface, next devoted itself to the prominences, 

 tin -n took up the corona, and with the invention of 

 the dry plate has gone back to detail on the surface 

 ami within tin- sun spots. The dry plate has been 

 tin- most important improvement which has con- 

 tributed to tlic advance of astronomical photog- 

 raphy. With the old wet processes the time of ex- 

 posure was limited ; it was not so flexible a method, 

 and was most inconvenient. A most important 

 brunch of investigation is that of stellar photog- 

 raphy, which dates practically from 1882. In an 

 fin leaver to catch the great comet of that year. Dr. 

 Gill, at the Cape of Good Hope, secured the assist- 

 ance of a local photographer, and when his pictures 

 reached Europe the astonishing feature was the 

 number of stars that they showed. The work has 

 been taken up with energy by many observatories, 

 and most excellent results" have been accomplished. 



A portion of Dr. Barnard's paper was devoted 

 to recent work, especially that of Lick and Harvard, 

 and an insight was given into the many different 

 lines of research wherein the camera plays an im- 

 portant part such as the noting of variable stars, 

 the securing of plates whereupon positions may be 

 measured^ the catching of the details of nebula? and 

 comets, and the discovery of asteroids. 



Alexander Ziwet, of the University of Michigan, 

 who was chosen secretary of this section last year, 

 having declined election, his place was filled by the 

 election of Winslow Upton, of Brown University. 



The following-named papers were read and dis- 

 cussed before the section: "Making Astronomy 

 Popular," by Miss Mary Proctor; "Correction of 

 Local Error in Stellar Photometry," by Henry M. 

 Parkhurst ; "The Parallaxes of 61' and 61 2 Cygni 

 from a Reduction of the Rutherfurd Measures, by 

 Herman S. Davis ; " The Pra>sepe Group : Measure- 

 ment and Reduction of the Rutherfurd Photo- 

 graphs," by Frank Schlesinger ; " Discordances be- 

 tween the" North Polar Distances of Stars derived 

 from Direct and Reflected Observations " and " The 

 Treatment of Results from Reflection Observations 

 at the Greenwich Observatory," by John R. East- 

 man ; " A Summary of. Planetary Work at the 

 Lowell Observatory, and the 'Conditions under 

 which such Work has been performed," by Andrew 

 K. Pougla>s ; " Astronomy in Southern California," 

 by Lewis Swift ; " A Description of Instantaneous 

 A/imnth and Altitude Charts of the Heavens," by 

 F. W. ('oar; "Instruction in Elementary Astron- 

 omy by Means of Observations made bv the Stu- 

 dent," by W. .Maxwell Reed ; Personal Equations 

 during the Past Century: A Brief Summary," by 

 Truman II. Sa fiord; "On Rational Etight-Angled 

 Triangle-. II." by Dr. Artemus Marl in : " Behavior 

 of the Atmospheres of (las- and Vapor-Generating 

 Globes in Celestial Space." by J. Woodbridge Davis ; 

 "Graphical Logic." by Kllen' Hayes ; " Illustrations 

 of the Coinitant Method of constructing the Imagi- 

 nary Loci of Analytical Geometry, so as to render 

 Their Properties Kvidetit to the Eye." by Frank 11. 

 Loud ; " On the Operation Groups of Order 48 and 

 tho-c of Order 2p*, p being any Prime Number," by 

 George A. Miller: " The Condition of the Surface 

 of the Planet Jupiter," by George W. Hough ; "The 

 Yerkes Observatory and its Work," by George E. 



Hale; "The General Theory of Anharmonics," by 

 Edgar 0. Lovett ; " On the Aims of the Interna- 

 tional Society for the Promotion of Quaternions 

 and Allied Branches." by Alexander Macfarlane ; 

 " Some Notes on ' Direction,' " by S. Edward War- 

 ren ; " A Short Method for deriving Riemann's 

 Theta Formula," by Franklin A. Becher ; " A Ter- 

 nary and a Quaternary Linear Congruence Group 

 simply Isomorphic to the Linear Fractional Con- 

 gruence Group," by Leonard E. Dickson ; " Linear 

 Transformations in Four Dimensions," by Arthur 

 S. Hathaway; "The Limitations of the Present So- 

 lution of the Tidal Problem," by John S. Hayford ; 

 " Variation of Latitude at New York City and the 

 Constant of Aberration from Observations with a 

 Zenith Telescope (Talcott's Method) at Columbia 

 University Observatory during the Years of 1892- 

 1898," by John K. Rees, Harold Jacoby, and Herman 

 S. Davis ; " Fifty Years of American Geodesy," by 

 Edward D. Preston ; " On the Duplex Base Ap- 

 paratus of the United States Coast and Geodetic 

 Survey " and " On the Diminution of the Refrac- 

 tion of the Atmosphere with Height and its Effect 

 upon Trigonometrical ly Determined Elevations 

 from Reciprocal Zenith Distances," by William 

 Eimbeck ; " On a New Application of the Prismatic 

 Camera to Total Eclipse, by David P. Todd ; " On 

 Harmonic Functions," "A Proposed Tidal Ana- 

 lyzer." "A Tidal Abacus," and "The Harmonic 

 Analysis of High and Low Waters," by Rollin A. 

 Harris ; and " A Description of the Altazimuth 

 Instrument recently constructed for the United 

 States Naval Observatory," by George A. Hill. 



Also the following reports were read : On 

 "Theory of Invariants: The Chief Contributions 

 of a Decade," by Henry S. White, and on "The 

 Modern Group Theory," by George A. Miller. 



A joint session was held with Section B, on Aug. 

 25, at which the following reports were read : " Re- 

 port on the Recent Progress in the Dynamics of 

 Solids and Fluids," by Ernest W. Brown", and " Re- 

 port on the Recent Progress in the Mathematical 

 Theory of Electricity and Magnetism," by Arthur C. 

 Webster ; also the following papers : " The Mass and 

 Moments of Inertia of the Earth's Atmosphere," 

 " Two New Forms of Apparatus for measuring the 

 Acceleration of Gravity," and " The Gravitation 

 Constant and the Mean Density of the Earth," by 

 Robert S. Woodward, and " The Limitations of 

 the Present Solution of the Tidal Problem," by 

 John S. Hayford. 



B. Physics. The presiding officer of this section 

 was Prof. Frank P. Whitman, of Adelbert College, 

 Cleveland, Ohio, who presented an address on 

 " Color Vision." This address was a summary of 

 the progress in the department of the vision of colors, 

 referring to the history of the research and sum- 

 ming up the matter in a statement of its condition 

 at -present. With a groundwork of the first definite 

 and intelligible hypothesis, that of Sir Isaac New- 

 ton, Prof. Whitman related the story of color vi- 

 sion, noting the improvements to the original hy- 

 pothesis suggested by Thomas Young, and finally 

 those of his successors in this line of investigation. 

 Color blindness was of course the burden of much 

 of the address, the various ideas that have been ad- 

 vanced to account for the false appreciation of col- 

 ors being passed in review. Much was said about 

 the "visual purple," the purpose of which has been 

 a puzzle to all anatomists. With reference to our 

 present knowledge, it seems clearly proved that the 

 number of color sensations is small and all hypoth- 

 eses that a large number are, he said, untenable 

 to-day. The vision of white light is by no means a 

 compound sensation, no matter how complex the 

 light may be physically, but at the same time it is 

 not a purely independent one, for there are some 



