34 BULLETIN Ob' THE 



15th Meeting. November 18, 18T1. 



The President in tlie Cliaii'. 



The meeting was opened by the delivery of the annual address 

 of the President. 



{This Address ivill'he found printed in full in the introductori/ portion of this 



volume.') 



A letter to Professor Henry from Dr. Bessels was read, dated 

 on board the Polaris, August 16th, giving some account of the 

 scientific operations of the North Pole Expedition up to that 

 date. 



Prof. W. Harkness read a paper 



ON THE SPECTRUM OF ENOKE'S COMET, AND THE APPEARANCE OF 

 TUTTLE'S COMET. 



{This paper is essentially as published in Washinrjton Astronomical Observa- 

 tions, 1870, Appendix II., pp. 25-49.) 



Dr. B. P. Craig made a communication 



ON apothecaries' WEIGHTS AND MEASURES. 



16th Meeting. December 2, 1871. 



The President in the Chair. 

 Prof. A. Hall read a paper 



ON THE ASTRONOMICAL PROOF OF THE EXISTENCE OF A RESISTING 

 MEDIUM IN SPACE. 



{This paper is published in fidl in the American Journal of Science and 

 Arts (3), vol. a. pp. 404-408, Dec. 1871.) 



Prof. W. Harkness made a verbal communication regarding 

 some singular results that he had lately arrived at by the study 

 of the spectrum of Encke's comet. 



{The substance of this communication xoill be found in Washington Astronomi- 

 cal Observations, 1870, Appendix II., pp. 25-49.) 



