138 



second time read. The line, bisecting tlic angle given by these two 

 readings, is the magnetic meridian, as indicated by the needle of the 

 instrument. To show the accuracy of which this method is suscep- 

 tible, he mentioned that, on the occasion referred to, the angle of 90° 

 was measured by the needle, on the first trial to within three minutes 

 and thirty seconds, on the second to within two minutes; and that in 

 no case afterwards did the error amount to one minute, and frequently 

 it was less than thirty seconds. He expressed the opinion that 

 any one accustomed to the use of instruments may obtain equally 

 satisfactory results. In conclusion he deemed it proper to state that 

 the theodolite used was made by Mr. Edward Draper, Mathematical 

 Instrument Maker, of Philadelphia. 



Dr. Hays announced the decease of Professor de Candolle, 

 of Geneva, a member of the Society. 



Mr. Kane informed the Society that the Secretaries had ap- 

 pointed Dr. Bache, Reporter, and Dr. Dunglison, Correspond- 

 ing Secretary for the present year. 



Mr. Lea, Chairman of the Publication Committee, laid upon 

 the table the First Part of Volume VIII. of the Society's Trans- 

 actions; and Mr. Kane, late Reporter, the closing Number for 

 1841 of the Proceedings. 



Dr. Patterson, on behalf of the Committee on the Museum 

 property, requested authority to memorialize the Legislature 

 for a grant of the necessary powers, to enable the Society to 

 make disposition of the Hall now occupied by it; which re- 

 quest, on motion, was granted. 



On motion of Prof. A. D. Bache, the Curators were requested 

 to receive the standards of measure, left by Mr. Vaughan to 

 the Society, and to have them placed in suitable cases and de- 

 posited in the Cabinet. 



Special Meeting, January 15. 



Present, fourteen members. 



Mr. Du Ponceau, President, in the Chair. 



The President announced the death of Joseph Hopkinson, 

 one of the Vice-Presidents, which occurred this dav? in the 



