106 



SCIENCE. 



[N. S. Vol. XII. No. 290. 



' History of the Complex Number,' by G. T. Sellew. 



' The Motion of a Top taking into account the 

 Eotatiori of the Earth,'** by A. S. Chessin. 



' Kelvin's Treatment of Instantaneous and Perma- 

 nent Sources extended to certain cases in which a 

 Source is in Motion,'** by James McMahon. 



'Oscillating Satellites',** by F. E. Moulton. 



' On a Mechanism for drawing Trochoidal and allied 

 Curves,'** by F. Morley. 



'On Surfaces sibi-reoiprocal under those contact 

 Transformations which transform Spheres into 

 Spheres,'** by P. F. Smith. 



' On Singular Transformations in the Keal Projec- 

 tive Group of the Place,'** by H. B. Newson. 



' Report on Groups of an Infinite Order,' by G. A. 

 Miller. 



' On the Metabelian Groups whose Invariant Oper- 

 ators form a Cyclical Subgroup, ' by W. B. Fite. 



' Definitions and Examples of Galois Fields,' by L' 

 E. Dickson. 



' Construction Problems in non-Euclidean Geom- 

 etry,' by G. B. Halsted. 



' The Expression of a Rational Polynomial in a 

 Series of Bessel Functions of the jith Order,' by 

 James McMahon. 



' Sundry Metrical Theorems connected with a spec- 

 ial Curve of the 4th Order, ' by F. H. Loud. 



' The Directive Force of Philosophy upon Mathe" 

 matics, ' by Miss M. E. Trneblood. 



'Die Hesse'sche und die Cayley'sohe Curve,' ** 

 by Paul Gordan. 



' On the Rational Quartic Curve in Space,'** by F- 

 Morley. 



' On a Special Form of Annular Surfaces, '** by 

 Virgil Snyder. 



'On Hyper-complex Number Systems,'** by H. E. 

 Hawkes. 



' Application of a Method of d'Alembert to the 

 Proof of Sturm's Theorem of Comparison,' ** by 

 Maxime Bocher. 



'Theorems on Imprimitive Groups,'** by H. W. 

 Kuhn. 



' A Simple Proof of the Fundamental Cauohy Gour- 

 sat Theorem,** by E. H. Moore. 



' On the Existence of the Green's Function for sim- 

 ply connected plane Regions bounded by a general 

 Jordan Curve, and for Regions having a more general 

 Boundary of positive Content,'** by W. F. Osgood. 



'Quaternions and Spherical Trigonometry,'** by 

 J. V. Collins. 



' The Reduction of Binary Quantics to Canonical 

 Form by Linear Transformation,'** by Miss B. E. 

 Grow. 



** American Mathematical Society paper. 



' Some Remarks on Tetraedral Geometry,'** by H. 

 E. Timerding. 



Organized discussion of the question. What courses 

 in Mathematics should be offered to the student who 

 desires to devote one-half, one-third, or one-fourth of 

 his undergraduate time to preparation for graduate 

 work in Mathematics.** Opened by J. Harkness, 

 E. H. Moore, F. Morley, W. F. Osgood and J. W. A. 

 Young. 



Wendell M. Steong, 



Secretary. 



PHYSICS AT THE A3IEBICAN ASSOCIATION. 



It was happily arranged this year that 

 the Physical Society should meet with Sec- 

 tion B, and this contributed to ensure a 

 better attendance than was at first antici- 

 pated. 



There were 29 papers presented before 

 Section B, and 13 before the Physical So- 

 ciety. All but four were read. 



The prominent characteristic of the pa- 

 pers presented was the care and thorough- 

 ness with which the experimental work 

 forming the basis of the communications 

 had been carried out. In this we see the 

 influence of the German University train- 

 ing which so many of our physicists have 

 received, but in addition to this there is su- 

 peradded an ingenuity, and an adaptation 

 of means to an end which is peculiarly 

 American, and the result is a series of 

 papers of the most admirable character. 



Possibly the paper which excited most 

 general interest was that of Professor R. 

 W. "Wood, on the ' Photography of Sound 

 Waves. ' The excellent photographs of the 

 sound waves themselves, in practically 

 every phase of transmission and reflection, 

 and the kinetoscopic reproductions of their 

 movement certainly marked an epoch in 

 the historj' of the subject. A second paper 

 'On the application of the Schlieren method 

 to the microscope,' illustrated a method ap- 

 parently destined to be of the greatest value. 



Another extremely valuable paper was 

 that of Dr. Bedell, on ' Copper Saving in 



**'American Mathematical Society paper. 



