606 



SCIENCE 



[N. S. Vol. XXV. No. 642 



presented: numbers 1 and 5 being contrib- 

 uted by the Mathematical Society, 2 and 4 

 by the Astronomical and Astrophysical 

 Society, 3, 6 and 7 by Section A. 



1. The Bational Basis of Mathematical 

 Pedagogy: Professor S. E. Slocum, Uni- 

 versity of Cincinnati. 



2. Photographic Ohservations of the Milky 

 Way: Professor E. E. Barnakd, Terkes 

 Observatory. 



3. The Stream Function for a Straight 

 Channel with a Circular Island: Pro- 

 fessor James McMahon. 



4. The Tenth Satellite of Saturn: Professor 

 W. H. Pickering, Harvard University. 



5. On the Law of Gravitation in the Binary 

 Systems: Dr. P. L. Grippin, Williams 

 College. 



6. Latitude Terms of Long Period: Pro- 

 fessor C. L. DOOLITTLE. 



7. Dynamical Trajectories: Dr. Edward 

 Kasneb. 



Abstracts of 1 and 5 of the above papers 

 appear in the Bulletin of the American 

 Mathematical Society, Vol. VIII., pp. 265, 

 266; of 2, 4 and 6, in the report of the 

 eighth annual meeting of the Astronomical 

 and Astrophysical Society of America, in 

 Science for April 12. The others will be 

 further noticed below. 



The full list of papers appearing upon 

 the program of Section A, with such ab- 

 stracts of the same as are available, is as 

 follows : 



An Examination of the Results of Seven 

 Years' Observation with the Zenith Tele- 

 scope of the Flower Observatory for 

 Latitude Terms of Long Period: Pro- 

 fessor C. L. DooLiTTLE, University of 

 Pennsylvania, Philadelphia. 

 A Preliminary Report on a Solar Rotative 

 Period Investigation: Mr. Philip Fox, 

 Terkes Observatory, "Williams Bay, Wis. 

 The preliminary investigation of the 



solar rotation period which was made, 

 under Mr. Hale's direction, by measuring 

 calcium flocculi positions on the Kenwood 

 series of spectroheliograms (Science, N. S., 

 XXI., 175), is now being supplemented by 

 a reduction of the measurements of the 

 plates made with the Rumford Spectro- 

 heliograph. One hundred of these plates 

 obtained in 1904 give the following results : 



The periods are thus seen to have been 

 longer in 1904 than in 1893-4r-5, the period 

 covered by the Kenwood series. The plates 

 of 1905 and 1906 are about to be measured. 



The Retrograde Motion of Phoebe: Mr. A. 

 0. Granger, Philadelphia, Pa. (Read 

 by title.) 



The Sect-carrier and the Set-sect: Professor 

 G. B. Halsted, State Normal College, 

 Greeley, Colo. 



The school of Plato fixed as the instru- 

 ments for the solution of geometric prob- 

 lems, the ruler and compasses, the straight 

 line and circle. As in Euclidean geometry 

 the straight line is a circle (of infinite 

 radius) and as Euclid unconsciously made 

 in his very first proposition the 'assump- 

 tion of the compasses,' that "If a circle 

 have a point within and a point without 

 another circle, it has two points on this 

 other" (Halsted, 'R. Geom.,' VI., 2), the 

 world has had to await the coming of the 

 non-Euclidean geometry to become con- 

 scious of the fact that elementary geometry 

 has been carrying a wholly unneceBsary 

 ' rider. ' 



