PHILOSOPHICAL SOCIETY OP WASHINGTON. 35 



Mr. Joseph Henry read an eulogy 



ON THE LIFE AND SCIENTIFIC LABORS OF THE LATE ALEXANDER 

 DALLAS BACHE, 



who was one of the founders of the scientific club from which 

 this society took its origin. 



(This Eulogy is published in full in the Report of the Secretary of the 

 Smilhsoniati Institution for 1870, Appendix, pp. 90-106.) 



Hth Meeting. December 16, 18T1. 



The President in the Chair. 

 Mr. J.'E. HiLGARD read a paper 



ON THE WESTWARD MOVEMENT OF THE POPULATION OF THE UNITED 



STATES. 



(This paper is published under the title, "The Advance of Population in the 

 United Slates,'^ in Scribner^s Mpnthbi Magazine, vol. iv., pp. 214-218, 

 ^ June, 1872.) 



Mr. C. S. Peirce read a paper 



ON THE APPEARANCE OF ENCKE'S COMET AS SEEN AT HARVARD 

 COLLEGE OBSERVATORY. 



(The substance of this communication will be publi.died in the Annals of the 

 Harvard College Observatory.) 



1 



Mr. E. B. Elliott made a communication 



ON THE LOCUS OF THE POINT OF EQUAL ILLUMINATION BY TWO 

 UNEQUAL LIGHTS TREATED BY THE QUATERNION ANALYSIS. 



Mr. Cleveland Abbe read a letter from Mr. S. A. King, 



aeronaut, of Boston, 



ON THE AERIAL CURRENTS OBSERVED IN FIFTY BALLOON 



ASCENSIONS. 



The thanks of the Society were returned to Mr. King for his 

 communication. 



