CONTENTS TO VOLUME XX. 



Number 115, 



Art. I. — Iodine Til. "~m Voltameter ; by D. A. Kreider . 1 

 II. — Handling of Preci x ites for Solution and Reprecipita- 



tion ; by F. A. Goou . _ _ _ 11 



III. — Estimation of Sulphites by Iodine ; by R. H. Ashley 13 

 IV. — Revision of the New York Helderbergian Crinoids ; 



by M.Talbot. (With Plates I-IV) 17 



V. — Petrographic Province of Central Montana ; by L. V. 



Pirsson . . _ 35 



VI. — Croomia pauciflora ; by T. Holm . _ _ _ _ . 50 



VII. — Relative Proportion of Radium and Uranium in 



Radio-active Minerals; by E. Rutherford and B. B. 



Boltwood 55 



VIII. — Side Discharge of Electricity ; by J. Trowbridge .. 57 

 IX. — Effect of High Temperatures on the Rate of Decay of 



the Active Deposit from Radium ; by H. L. Bronson.. 60 



SCIENTIFIC INTELLIGENCE. 



Chemistry and Physics — Amounts of Neon and Helium in the Air, W. Ram- 

 say : Radio-activity of Thorium, 0. Sackur, 65. — Use uf Quartz Apparatus 

 for Laboratory Purposes, Mylius and Metjsser : Permeability of Quartz 

 Vessels to Gases, Berthelot : Outlines of Inorganic Chemistry, A. Gooch 

 and C. F. Walker, 66. — Spectroscopic Analysis of Gas Mixtures, J. E. 

 Lilienfeld : FitzGerald-Lorentz Effect, Morley and Miller, 67. — Normal 

 Element : Influence of Character of Excitation upon Structure of Spectral 

 lines : Radio-active Minerals, R. J. Strutt : Absence of excited Radio- 

 activity due to temporary Exposure to y-Rays, 68. — Handbuch der Spectro- 

 scopic, H. Kayser, 69. 



Geology and Natural History — United States Geological Survey, 69. — Pre- 

 liminary Report on the Geology and Underground Water Resources of the 

 Central Great Plains, N. H. Darton, 70. — Origin of the Channels surround- 

 ing Manhattan Island, New York, W. H. Hobbs, 71. — Isomorphism and 

 Thermal Properties of the Feldspars, A. L. Day and E. T. Allen, 72. — 

 Tin Deposits of the Carolinas, J. H. Pratt and D. B. Sterrett : Tubico- ' 

 lous Annelids of the Tribes Sabellides and Serpulides from the Pacific 

 Ocean, K. J. Bush, 75.— Student's Text-Book of Zoology, A. Sedgwick : 

 Preliminary Report on the Protozoa of the Fresh Waters of Connecticut, 

 H. W. Conn, 76. — Etudes sur lTr-stinct et les Moeurs des Insects, J.-H. 

 Fabre : Rocky Mountain Goat, M. Grant : Catalogue of North American 

 Diptera (or two-winged Flies), J. M. Aldrich : Fauna and Geography of 

 the Maldive and Laccadive Archipelagoes, J. S. Gardiner : American 

 Museum Journal, 77. — Cold Spring Harbor Monographs, 78. 



Miscellaneous Scientific Intelligence — Vom Kilimandscharo zum Meru, C. 

 Uhlig, 78. — Glacial Studies in the Canadian Rockies and Selkirks, W. H. 

 Scherzer : Solar Observatory of the Carnegie Institution of Washington, 

 G. E. Hale : United States Naval Observatory : Publications of West 

 Hendon House Observatory, Sunderland, 80. 



