848 



SCIENCE. 



[N. S. Vol. XIV. No. 361. 



Eeduction of Hyperelliptic Integrals of Genus 

 Two to Elliptic Integrals by a Transformation 

 of the Fourth Order,' by J. H. McDonald ; ' On 

 the Theory of Improper Definite Integrals,' by 

 E. H. Moore ; ' On the Convergence and Char- 

 acter of a Certain Form of Continual Fraction,' 

 by E. B. Van Vleck ; Notes and Errata, Vol- 

 umes 1 and 2. 



The October number (Volume 8, No. 1) of 

 the Bulletin of the American Mathematical Society 

 contains the following articles : ' The Eighth 

 Summer Meeting of the American Mathematical 

 Society,' by F. N. Cole; 'The Ithaca Collo- 

 quium,' by Edward Kasner; 'Upon the Non-Iso- 

 morphism of two Simple Groups of Order 8!/2,' 

 by Ida M. Schottenfels ; ' Concerning Surfaces 

 whose First and Second Fundamental Forms are 

 the Second and First Fundamental Forms re- 

 spectively of another Surface,' by Alexander 

 Pell; 'Notes,' and 'New Publications.' The 

 November number of the Bulletin contains : ' On 

 Wronskians of Functions of a Real Variable,' 

 by Maxime Bocher ; ' The Configurations of the 

 27 Lines on a Cubic Surface and the 28 Bitan- 

 gents to a Quartic Curve,' by L. E. Dickson; 

 ' The Fiftieth Annual Meeting of the American 

 Association for the Advancement of Science,' 

 by G. A. Miller ; ' Riemann- Weber : Partial Dif- 

 erential Equations of Mathematical Physics,' 

 by J. S. Ames; 'Notes,' and 'New Publica- 

 tions.' 



SOCIETIES AND ACADEMIES. 

 AMERICAN PHYSICAL SOCIETY. 



The fall meeting of the American Physical 

 Society was held at Columbia University on 

 Saturday, October 26, President Michelson pre- 

 siding. The first paper, by F. L. Tufts, de- 

 scribed experiments on the effects of stationary 

 sound waves on unignited gas jets. The dis- 

 turbances caused in such jets by sound waves 

 were made visible by means of the ' Schlieren 

 Methode,' the source of illumination being the 

 spark of an induction coil. The jet was found 

 to assume a vibrating sinuous form, with in- 

 creased amplitude at greater distances from the 

 orifice. The results could be explained upon 

 the assumption that the initial velocity of the 

 gas, upon issuing from the orifice, is the re- 



sultant of its own proper velocity and that due 

 to the vibration of the sound wave. Photo- 

 graphs of unignited jets when disturbed in this 

 way were shown. A second paper by Mr. 

 Tufts dealt with experiments with the ordinary 

 organ pipe. The Schlieren method was ap- 

 plied in this case to show the vibrations of the 

 blast of air blown against the tongue of the 

 pipe, and photographs were shown which gave 

 excellent confirmation of the usual theory of 

 the action of such pipes. 



A note on the use of the Arous' mercury 

 lamp as a source of illumination in certain color 

 experiments was presented by Ernest Merritt. 

 The light from the mercury arc is chiefly due to 

 three lines in its spectrum, lying respectively 

 in the violet, the green and the yellow. These 

 lines are sufficiently near to the three primary 

 colors to make the light of the lamp seem not 

 greatly different fi'om white ; but when the 

 lamp is used to illuminate colored objects the 

 absence of the red is rendered evident. Red 

 objects, for example, usually appear black when 

 seen by this light. When a selection is made 

 from colored worsteds, such as are used in the 

 ordinary test for color-blindness, the selections 

 are much the same as those made by a red-blind 

 individual. 



After the noon recess the Physical Society 

 joined with the Mathematical Society during 

 the reading of a paper by M. Hadamard on 

 the ' Theory of Elastic Plates. ' In the after- 

 noon session a note was presented by Wm. 

 Hallock on ' Measurements of Subterranean 

 Temperatures,' in which were given the results 

 of the most recent work on this subject. An 

 instrument for the measurement of entropy 

 was described by A. G. Webster. This ' en- 

 tropy meter ' had not been actually constructed, 

 nor did the speaker think that it would make a 

 very practical apparatus. It showed a possible 

 method, however, by which entropy changes 

 might be automatically registered and meas- 

 ured. Mr. Webster also reported the results 

 of experiments upon the audibility of sound 

 over grass and water. It was found that under 

 similar conditions of quietness, etc., a given 

 sound could be heard almost exactly four times 

 as far over water as over grass. The assump- 

 tion that water is a perfect reflector, while grass 



