IV CONTENTS. 



Number 200. 



Page 



Art. IX. — Interferometry of Air Carrying Electrical Cur- 

 rent ; by C. Barus . 101 



X. — Electrolytic- Analysis with Platinum Electrodes of Light 



Weight ; by F. A. Gooch and W. L. Burdick 107 



XI. — Siliceous Oolites of Central Pennsylvania ; by V. 



ZlEGLER 113 



XII. — Composition, Structure, and Hardness of Some Peru- 

 vian Bronze Axes ; by H. W. Foote and W. H. Buell 128 



XIII. — Photoelectric Effect of Phosphorescent Material ; by 



C. A. Butman .- __ 133 



XIV. — Tertiary Fungus Gnat ; by O. A. Johannsen 140 



XV. — Heat of Formation of the Oxides of Vanadium and 

 Uranium, and Eighth Paper on Heat of Combination of 

 Acidic Oxides with Sodium Oxide ; by W. G. Mixter 141 



XVI. — Chattanoogan Series with Special Reference to the 



Ohio Shale Problem ; by E. O. Ulrich 157 



XVII. — Pseudomorphs after Stibnite from San Luis Potosi, 



Mexico; by W. E. Ford and W. M. Bradley 184 



XVIII. — Stratigraphic Relations of the Devonian Shales of 



Northern Ohio ; by E. M. Kindle 187 



XIX. — Estimation of Titanium in the Presence of Iron ; by 



W. M. Thornton, Jr 214 



XX. — Pleistocene Plants from the Blue Ridge in Virginia ; 



byE. W. Berry ". 218 



SCIENTIFIC INTELLIGENCE. 



Geology and Natural History — Age of the Plant-bearing Shales of the Rich- 

 mond Coal Field, E. W. Berry, 224. — Geological Survey of New Jersey : 

 Topographic and Geologic Survey of Pennsylvania : State Geological Sur- 

 vey of Wyoming, 225. — Maryland Geological Survey : Cape of Good Hope, 

 Department of Mines, 15th Annual Eeport of the Geological Commission, 

 1910, 226.— Monograph of the British Desmidiaceae, W. West and G. S. 

 West: Elementary Plant Biology, J. E. Peabody and A. E. Hunt : Illus- 

 trated Key, etc., J. F. Collins and H. W. Preston, 227. 



Miscellaneous Scientific Intelligence — Introduction to Analytic Mechanics, 

 A. Ziwet And P. Field, 228. 



Obituary — F. Zirkel : E. Strasburger : W. M. Woodworth : M. L. db 



BOISBAUDRAN, 228. 



