CONTENTS. 



PAGE 



1. Applications of FresneVs Formula for the Reflection of Light. 



By Edward C. Pickering 1 



II. Report of Committee appointed to memorialize the Legislature of 

 the Slate of Massachusetts on the subject of Expert Testimony. 

 By Emory Washburn . 31 



in. The Vermiculites : their Crystallographic and Chemical Rela- 

 tions to the Micas : together loiih a Discussion of the Cause 

 of the Vaination of the Optical Angle in these Minerals. 

 By Josiah p. Cooke, Jr 35 



IV. An Asexual Growth from the Prothallus of Pteris serrulata. 



By William G. Farlow, M.D 68 



V. On a Practical Test of the Condition and Composition of Nat- 

 ural Waters. By Aug. A. Hayes, M.D 78 



VI. A Revision of the North American Chenopodiacece. By Sereno 



Watson 82 



VII. On the Periodic Errors of the Right Ascensions observed between 



1858 and 1871. By William A. Rogers 127 



VIII. Scientific Survey of the State of Massachusetts. Memorial to 



the General Court 184 



IX. Notes on Compositce and Characters of Certain Genera and 



Species. By Asa Gray 187 



X. A Singular Case of Corrosion of a Tin Tank. By S. P. 



Sharples 219 



XI. Applications of the Graphical Method. By Edward C. Pick- 

 ering 222 



XII Ocean Lanes for Steamships. By Benjamin Peirce . . 228 

 Proceedings 231 



