CONTENTS. 



Niimlber 177. 



Page 

 Art. XV. — Use of the Grating in Interferometiy, by C. 



Bartjs '- 161 



XVI. — Fox Hills Sandstone and Lance Formation ("Ceratops 

 Beds") in South Dakota, North Dakota and Eastern 

 Wyoming, by T, W. Stanton 172 



XVII. — New Occurrence of Hydrogiobertite, by R. C. Wells 189 



XVIII. — New Occurrence of Plumbojarosite, byW. F. Hille- 



BKAND and F, E. Wright 191 



XIX. — Heat of Formation of the Oxides of Cobalt and 

 Nickel ; and sixth paper on the Heat of Combination 

 of Acidic Oxides with Sodium Oxide ; by W. G. Mixter 193 



XX. — Mosesite, a New Mercury Mineral from Terlingua, 

 Texas, by F. A. Canfield, W. F. Hillebrand, and W. 



T. SCHALLER - - - 202 



XXI. — Researches upon the Complexity of Tellurium, by 



W. R. Flint 209 



XXII. — Gravimeti'ic Estimation of Vanadium as Silver 



Vanadate, by P. E. Browning and H. E. Palmer 220 



XXIII. — Brachiopod genus Syringothyrisin the Devonian of 



Missouri, by C. Schuchert 223 



George Frederic Barker 225 



