232 



Slated Meeting, April 21, 1876. 

 Present, 17 members. 



Vice-President, Mr. Fiialey, in the Chair. 



Letters of acknowledg^njent were received from the Insti- 

 tute National de France, dated March 31, (XEV iii, and 

 asking for Vol. V i, N. S. and XLV ii), from the Rad- 

 cliffe Observatory, Oxford, March oO, and fmm the New 

 York State Library, April 15. 



Donations for the Library were received from the Prus- 

 sian Academy, Aimales des Mines, Nous'ell&s Meteorolo- 

 giques, Revue Politique, Nature, Mus. Comp. Zool, Mass., 

 American Chemist, Cap. Jas. C. Cole, Franklin Institute, 

 Am. Jour. Med. Sciences, and Mr. A. IL Worthen, of Spring- 

 field, Illinois. 



Dr. Ruschenberger was, on motion, substituted for Dr. 

 Ilartshorne on the Committee to report on the publication 

 of the medical theses presented at the last meeting, at there- 

 quest of the latter. 



Dr. Ilartshorne read a paper on complementary spectra, re- 

 jecting the commonly received " Fatigue Theory," and of- 

 fering a new explanation based ui»on the interference of light 

 rays, ilhistrating his views by means of colored papers, and 

 the matj-nesian light. 



Prof. Chase communicated certain relationshi})S which lie 

 had worked out between the velocity of light and the rota- 

 tion of Mr. Crooke's new rotation api)aratus, and with the 

 phenomena of the "Silenium Eye." To these he added some 

 fresh calculations of the weights of the planets. 



Prof. Frazer read a communication whicii he had received 

 from Mr. Peyton Smith, C. E. of York, Pa., giving a 

 sketch of the literature of the belief in one magnetic pole 



