VI CONTENTS. 



Number 274. 



Page 



Art. XXIIT. — The Green River Desert Section, Utah; by 



W. B. Emery 551 



XXIV. —The Law of Dissipation of Motion; by E. Jonson. 578 



XXV. — An American Occurrence of Periclase and its Bear- 

 ing on the Origin and History of Calcite-Brucite Rocks; 

 by A. F. Rogers 581 



XXVI.— On the Preparation of Hypophosphates; by R. G. 



Va.nName and W. J. Huff 587 



XXVII. — Origin of the Western Phosphates of the United 



States; by G. R. Mansfield.. 591 



XXVIII. -Dustfall of March 9, 1918; by A. N. Winchell 



and E. R. Miller 599 



XXIX. — Note on a Universal Switch for Delicate Potential 



Measurements ; by W. P. White 610 



SCIENTIFIC INTELLIGENCE. 



Chemistry and Physics — Apparatus for Determining Molecular Weights and 

 Hydrogen Equivalents, W. H. Chapin, 613. — Detection of Iodides in the 

 Presence of Cyanides, L. J. Curtman and C. Kaufman : Determination of 

 Zinc as Zinc Mercury Thiocyanate, G. S. Jamieson: Principles of Chem- 

 istry, J. H. Hillebrand, 614. — Organic Compounds of Arsenic and Anti- 

 mony, G. T. Morgan: Edible Oils and Fats, C. A. Mitchell: Scattering 

 of Light by Dust- free Air, with Artificial Reproduction of the Blue Sky, 

 R. J. Strutt, 615. — Occurrence in the Solar Spectrum of the Ultra-violet 

 Bands of Ammonia and of Water-vapor, A. Fowler and C. C. L. Gregory, 

 617. — A Calendar of Leading Experiments, W. S. Franklin and B. Mac 

 Nutt, 618. 



Miscellaneous Scientific Intelligence — Journal of the Ceramic Society, 619. — 

 A Century of Science in America with especial reference to the American 

 Journal of Science, 1818-1918, 620. 



Obituary— R. Rathbun: S. F. Peckham: S. W. Williston, 620. 



