IV CONTENTS. 



Number 176. 



Art. VII. — Artificial Lava-Flow and its Spherulitic Crystal- 

 lization, by L. V. PiussoN. (With Plate I) 97 



VIII. — Inversion of Temperature Amplitudes and Depart- 

 ures in the United States, by F. H. Bigelow - - . . 115 



IX. — Effect of the Presence of Alkalies in Beryl upon 



its Optical Properties, by W. E. Ford '128 



X. — Correlation of the Guadalupian and the Kansas 



Sections, bj'^ J. W. Beede 131 



XI. — Application of Potassium Ferricyanide in Alka- 

 line Solution to the Estimation of Vanadium and Chro- 

 mium, by H. E. Palmer. _ 141 



XII. — Ludwigite from Montana, by W. T. Scfialler 146 



XIII. — Chemical and Optical Study of a Labradorite, 



by W. E. Ford and W. M. Bradley 151 



XIV.— Halley's Comet, by G F. Chambers 154 



SCIENTIFIC INTELLIGENCE. 



Geology — Cement Eesources of Virginia west of the Blue Eidge, R. S. Bass- 

 LEB : Proposed Groups of Pennsylvanian Rocks of Eastern Oklahoma, C. 

 N. Gould, D. W. Ohern and L. L. Hutchison : Yorkshire Type Ammon- 

 ites, S. S. BUCKMAN, 157. 



Miscellaneous Scientific Intelligence — Physical and Commercial Geography ; 

 A Study of Certain Conditions of Commerce, H. E. Gregory, A. G. Keller 

 and A. L. Bishop : Soil Fertility and Permanent Agriculture, C. G. Hop- 

 kins, 158 — Publications of the Smithsonian Institution, 1 60. 



Oftifwarj/— JoHANN Gottfried Galle : Dr. Charles Abiathar White, 160 



