356 
PHILOSOPHICAL SOCIETY OF WASHINGTON. 
Mr. L. A. BauEr read a paper on The general plan of the 
magnetic survey of the United States. [Published in U. S. Coast 
and Geodetic Survey Report for 1899, Appendix 10.] 
Remarks were made on this by Mr. Abbe. 
Mr. A. Macfarlane presented by invitation a paper on The 
square root of minus one. 
515th Meeting. March 17, 1900. 
President Sternberg in the chair. 
Thirty persons present. 
Mr. Gore spoke informally on the Residual of the Paris Expo¬ 
sition, and 
Mr. Littlehales gave the Results of a survey across the 
Pacific for a submarine cable from California to the Philippine 
Islands. [Not Published.] 
Mr. C. Abbe read a paper on Some recent contributions to 
Meteorology, [Not published.] 
Mr. L. P. Shidy made a Report on the state of progress in our 
knowledge of the tides. [Published in this volume, p. 117.] 
Mr. L. A. Bauer spoke on Some recent contributions to 
terrestrial magnetism, and exhibited many lantern slides of 
prominent meteorologists, magneticians, and observatories. 
[Published in the Journal of Terrestrial Magnetism, etc., vol. v, 
p. 85 (1900) ; Science, vol. xi, p. 651 (1900).] 
516th Meeting. 4 March 31, 1900. 
Past President Baker in the chair. 
Eleven persons present. 
Mr. Radelfinger spoke informally of The method of selecting 
professors in the higher institutions of learning in France, and 
Mr. Hayford made some remarks on The determination of the 
difference of elevation of two given points on the earth's surface. 
Mr. M. Baker read a biographical sketch of Samuel Shella- 
barger. [Published in the Bulletin, vol. xiii, p. 416.] 
