vin CONTENTS. 



Number 252. 



Page 

 Art. XLIV. — The Lava Eruption of Stromboli, Summer- 

 Autumn, 1915 ; by F. A. Pkbret. 443 



XLV. — Determination of Fluorine in Soluble Fluorides; by 



J. G. Dinwiddie 464 



XL VI.— The Albertella Fauna Located in the Middle 

 Cambrian of British Columbia and Alberta; by L. D. 

 Burling 4Q9 



XLVII. — Some New Forms of Natrolite; by A. H. Phillips 472 



XLVIII. — On Pre-Cambrian Nomenclature; by C. Schuchert 475 



XLIX.— Plotting Crystal Zones on Paper; by J. M. Blake. 486 



L. — A Graduated Sphere for the Solution of Problems in 



Crystal Optics; by C. H. Warren 493 



SCIENTIFIC INTELLIGENCE. 



Chemistry and Physics — Separation of Lithium from Potassium and Sodium, 

 S. Palkin: Action of Light upon Iodine and Iodide of Starch, M. H. 

 Bordier, 496. — Crystallization of Calcium Tartrate, F. D. Chattaway: 

 Basic Copper Sulphates, S. W. Young and A. E. Stearn, 497. — Determi- 

 nation of Chlorides in Presence of Thiocyanates. F. W. Bruckmiller: 

 New Method of Determining Refractive Indices, R. W. Cheshire, 498. — 

 Fluorescent Vapors and their Magneto-optic Properties, 499. — Problems in 

 Physics for Technical Schools, Colleges, and Universities, W. D. Hender- 

 son, 501.— General Physics, Third Edition, H. Crew, 502. 



Geology and Mineralogy — Coal Measures Amphibia of North America, B. L. 

 Moodie, 502. — Papers from the Geological Department, Glasgow Univer- 

 sity: West Virginia Geological Survey, I. C. White: Papers on Coal and 

 the Coal Industry, 503. — Notes on Radiolarian Cherts in Oregon: a Correc- 

 tion: New Mineral names, W. E. Ford, 504. 



Miscellaneous Scientific Intelligence — Centennial Celebration of the United 

 States Coast and Geodetic Survey. E. L. Jones, 505. — National Academy 

 of Sciences, 506. — American Association for the Advancement of Science, 

 507. — Publications of the Carnegie Institution of Washington, 508. 



Obituary — C. Abbe: P. Lowell: P. Duhem, 509. 



