VI CONTENTS. 



XI. Further Investigation on the Atomic Weight of Copper. By 



Theodore William Richards 177 



XII. Additional Note on the Relative Values of the Atomic Weights 

 of Hydrogen and Oxygen. By Josiah Parsons Cooke 

 and Theodore William Richards 182 



XIII. On Substituted Pyromucic Acids. Second Paper. By 



Henry B. Hill and Arthur W. Palmer . . . 188 



XIV. Contributions to American Botany. By Asa Gray . . . 223 



XV. Experiments on the Blake Microphone Contact. By George 



W. Patterson, Jr 228 



XVI. Boiling Points of Naphthaline, Benzophenone, and Benzol 

 under controlled Pressures, ivith special Reference to Ther- 

 mometry. By S. W. Holman and W. H. Gleason 237 



XVII. Contributions to American Botany. By Sereno Watson 249 



XVIII. Wave-Lengths of Metallic Spectra in the Ultra Violet. By 



John Trowbridge and W. C. Sabine 288 



XIX. Selective Absorption of Metals for Ultra Violet Light. By 



John Trowbridge and W. C. Sabine 299 



XX. Photography of the Least Refrangible Portion of the Solar 



Spectrum. By J. C. B. Burbank 301 



Proceedings 305 



Memoirs : — 



Alvan Clark 315 



Charles Smith Bradley # . . 317 



John Dean 319 



Asa Gray 321 



Laurens Perseus Hickock 343 



Mark Hopkins 314 



Charles Eliot Ware 346 



Spencer Fullerton Baird 347 



Samuel Gilman Brown 348 



