CONTENTS OF VOLUME XXXIX. 



Number 229. 



Page 



Art. I. — Measurement of the Peril vian Are ; by E. D. 



Preston 1 



II. — Neutralization of Induction ; by J. Trowbridge and 



S. Sheldon 17 



III. — Divergent Evolution and tbe Darwinian Theory ; by 



J. T. Gulick 21 



IV. — Devonian System of North and South Devonshire ; by 



H. S. Williams 31 



V. — Zinciferous Clays of Southwest Missouri and a Theory 

 as to the growth of the Calamine of that section ; by 



W. H. Seamox - - 38 



VI. — Minium from Leadville ; by J. D. Hawkins 42 



VII.— Mineralogical Notes; by W. P. Blake 43 



VIII. — Spectrum of Ursffi Majoris ; by E. C. Pickering 46 



IX. — Contributions to Mineralogy, No. 46 ; by F. A. Genth 47 



X. — Origin of Normal Faults ; by T. M. Reade 51 



XI. — Estimation of the Optical Angle by Observations in 



Parallel Light ; by A. C. Lane 53 



XII.— New Stone Meteorite ; by L. G. Eakins 59 



XIII. — Barium Sulphate from Perkins' Mill, Templeton, 



Province of Quebec ; by E. S. Dana ._ 61 



XIV. — Appendix. — Description of New Dinosaurian Rep- 

 tiles ; by O. C. Marsh. With Plate I _. 81 



SCIENTIFIC INTELLIGENCE. 



Chemistry and Physics. — Decomposition of Carbon disulphide by shock, Thorpe, 

 65.— Light and Electricity, Righi : Galvanic Polarization, Warburg : Simple 

 modification of the method of Telescope and Scale reading, DtjBois, 66. 



Geology and Mineralogy. — North American Geology and Palaeontology, S. A. 

 Miller : Geological and Natural History Survey of Minnesota for the year 

 1838, N. H. Wixchell, 67.— Geology of the Quicksilver Deposits of the Pacific 

 Slope, G. F. Becker, 68. — New locality of Lower Silurian Fossils in the Lime- 

 stones of Columbia Co., N. Y., I. P. Bishop, 69. — Shallow-water origin of the 

 Cincinnati shale and limestone : Lower Cretaceous of the San Carlos Mountains, 

 Mexico. 70. — Sabre-toothed tiger and other Quaternary Mammals of Florida, 

 J. Leidy : Fossils of the Western Taconic limestone in the eastern part of 

 Dutchess Co., N. Y.. W. B. D wight : Cambrian fossils from the limestone of 

 Nahant, Mass., A. F. Fcerste : Development of some Silurian Brachiopoda, C. 

 E. Beecher and J. M. Clarke : Devonian Plants from Ohio, J. S. Newberry, 

 71. — U. S. Geological Survey Bulletins: Geological Survey of Missouri. A. 

 Winslow: Geologie der Miinsterthals in Badischen Schwarzwald, A. Schmidt: 

 Contribuzioni alia Flora Fossile dei Terreni Terziarii della Liguria, S. Squixabol, 

 7 2. — Jarosite from Utah, F. A. Genth: Brief notices of some recently de- 

 scribed Minerals, 73. — Das Reich der Krystalle, H. Baumhauer, 75. 



Botany. — Die naturlichen Pflanzenfamilien, A. Engler und K. Prantl, 75. — 

 Effects produced on some tropical plants by a temperature of 40 to 34 degrees, 

 77. — Apparatus for easily controlling temperatures at or below freezing, for 

 experiments on the relations of plants to cold, 78. — Disintegration of woody 

 tissues : Illustrations of West American Oaks, A. Kellogg, 79. 



Miscellaneous Scientific Intelligence. — Ascent of a Peak in the Cascade Mountains, 

 J, Roll, 80. 



