

C X T E N T s . 



'a 



Art. XX VII. — Generalized Relativity and Gravitation ; by 

 E. Woolard .' 



XXVIII. — An Unusual Mastodon ; by F. B. Loomis 438 



XXIX. — A Restoration of Neocalamites ; by E. W. Berry 445 



XXX.— The Origin of Chert ; by F. M. Van Tuyl 449 



XXXI. — A Large Parasucbian from theTriassic of Pennsyl- 

 vania; by W. J. Sinclair 457 



XXXII. — Augite from Stromboli ; by S. Kozu and If. S. 



Washington. __ 463 



SCIENTIFIC INTELLIGENCE. 



Chemistry and Physic* — Use of Metallic Silver as a Reducing Agent in the 

 Volumetric Estimation of Iron, G. Edgar and A. R. Kemp : lodimetrio 

 Estimation of Copper and Iron, H. Ley, 470. — Chemistry in the Home, 

 H. T. Weed: Chemistry, First Stage, F. P. Armitage, 471.— Publications 

 of the Yerkes Observatory, G. E. Hale, etc., 472. — Axial Aberrations of 

 Lenses, E. D. Tillyer and H. I. Shultz, 474. 



Geology and Mineralogy — Publications of the United States Geological Sur- 

 vey, G. O. Smith, 475. — United States Bureau of Mines, V. H. Manning: 

 Geology and Ore Deposits of the Yirgiliua District of Virginia and North 

 Carolina, F. B. Laney, 47G. — Tin Deposits near Irish Creek, Virginia, H. 

 G. Ferguson : New Mineral Names, V. E. Ford, 477.— Geological Society 

 of London, 478. — A Geological Handbook to Northern France, W. M. 

 Davis, 479. 



Miscellaneous Scientific Intelligent — National Academy of Sciences, 479. — 

 Carnegie Institution of Washington, Year Book, No. 16, R. S. Woodward, 

 480. — Carnegie Foundation for the Advancement of Teaching, Twelfth 

 Annual Report of the President and Treasurer, H. S. Pritchett and R. A. 

 Franks, 483. — Soil Physics and Management, J. G. Mosier and A. F. 

 Gustafson : Elementary Economic Geography, C. R. Dryer, 484. — A 

 Laboratory Outline of Neurology, C. J. Herrick and E. C. Crosby, 485. 



Obituary— -G. K. Gilbert: G. J. Hinde, 485. 



Index, 480. 



Note. — A Centennial Number, dealing in twelve chapters with the his- 

 torical development of the Journal and of the different branches of Science 

 represented in its pages since its foundation in 1818, will be issued about July 

 first. It will contain about 400 pages ; price one dollar, to regular sub- 

 scribers without extra charge. 



313 



