OP ARTS AND SCIENCES. 475 



Six hundred and eightietli Meeting. 



May 11, 1875. — Monthly Meeting. 



The President in the chah\ 



The Corresponding Secretary presented, in print, the 

 Report of the Council for the past year, which is hereto 

 appended. He also read a letter from M. Thiers, acknowl- 

 edging his election as Foreign Honorary Member of the 

 Academy. The following scientific communications were 

 then made, but the first two were only read by title : — 



On the Application of Logical Analysis to Multiple Al- 

 gebra, by C. S. Peirce. 



On the Uses and Transformations of Linear Algebra, by 

 Benjamin Peirce. 



On the Intensity of Twilight, by Charles H. Williams. 



On the Light of the Sky, by W. O. Crosby. 



On Light Absorbed by the Atmosphere of the Sun, by 

 E. C. Pickering and D. P. Strange. 



On Tests of Magneto-Electric Machines, by E. C. Pickering 

 and D. P. Strange. 



Answer to M. Jamin's Objections to Ampere's Theory, 

 by William W. Jacques. 



On Melanosiderite : a New Mineral Species, from Mineral 

 Hill, Delaware County, Pennsylvania, by Josiah P. Cooke, Jr. 



On Two New Yermiculites, with a Revision of the other 

 Members of this Group of Minerals, by Josiah P. Cooke, Jr., 

 and F. A. Gooch. 



On a Possible Explanation of the Method employed by 

 Nobert in Ruling his Test Plates, by William A. Rogers. 



On the Solar Motion and Stellar Distances, second paper, 

 by T. H. Safford. 



