CONTENTS. 



Part III. Traces of Ancient Glaciers in Massachusetts and Vermont . 



Index ......... 



Explanation of the Plates . . 



PAGE 



129 



145 

 153 



ARTICLE IV. Observations on Mexican History and Archeology, with a special notice 

 op Zapotec Remains as delineated in Mr. J. G. Sawkin's Drawings op 

 Mitla, &c. By Brantz Mayer. Pp. 36, and four plates. 



ARTICLE V. Researches on the Ammonia Cobalt Bases 

 Frederick Aug. Genth. Pp. 72. 

 Introduction . . . . 



General Account of the Salts of Roseo-cobalt 

 General Account of the Salts of Purpureo-cobalt 

 General Account of the Salts of Luteo-cobalt 

 General Account of the Salts of Zantho-cobalt 

 Theoretical Considerations - . 



By WOLCOTT GlBBS AND 



1 



7 

 21 

 35 

 48 

 59 



APPENDIX. 



New Tables for Determining the Values of the Coefficients in the Perturbative Functions 

 of Planetary Motion, which depend upon the Ratio of the Mean Distances. By John D. 

 Runkle, Assistant in the office of the American Ephemeris and Nautical Almanac. November, 1856. 

 Pp. 64. 



Asteroid Supplement to New Tables, for Determining the Values of b<>> and its Derivatives. 

 By John D. Runkle, Assistant in the office of the American Ephemeris and Nautical Almanac. 

 May, 1857. Pp. 72. 



