PROCEEDINGS. 
391 
548th Meeting. March 1, 1902. 
Vice-President Gore in the chair. 
Thirty-two persons present. 
The usual committees were announced as follows: 
Committee on Mathematical Science. 
F. G. Radelfinger. C. Abbe. 
J. H. Gore. F. H. Bigelow. 
L. E. Dickson. 
Committee on Physical Science . 
C. F. Marvin. A. L. Day. 
C. Abbe. S. W. Stratton. 
L. A. Bauer. 
Committee on General Science . 
W. H. Dale. A. Lindenkohl. 
C. Adler. C. H. Merriam. 
A. C. Peale. 
Mr. Briggs spoke informally on A rainbow observed in the 
dew. Messrs. Abbe, Baker, Gilbert, Paul, and We ad joined in 
the discussion. 
Mr. Baker gave a brief account of the present status of the 
Carnegie Institution. 
Mr. D. L. Hazard read a paper on The secular variation of 
the magnetic declination in the United States. This change appears 
to be periodic, having a period of several hundred years and 
amounting to 5° to 8°. The Coast and Geodetic Survey has 
made observations for fifty years and has deduced certain gen¬ 
eral relations between the geographical location of a place 
and the terms of the formula expressing the declination. On the 
basis of these a new isogonic chart has just been issued. [A sum¬ 
mary of the U. S. Declination Tables, etc., for 1902, by L. A. 
Bauer, published by the Coast and Geodetic Survey.] 
In the discussion that followed Mr. Baker spoke of the 
voluminous magnetic records made by the surveyors of the Land 
