CONTENTS 



Page. 



Art. XXII. —The Absolute Wave-length of Light; by L. 



Bell . 265 



XXIII. — History of the changes in the Mt. Loa Craters ; by 



J. D. Dana. (With Plates IV and V) 282 



XXIV. — The Electromotive Force of Magnetization ; by 



E. L. Nichols and W. S. Franklin 290 



XXV. — Notes on certain rare Copper Minerals from Utah ; 



by W. F. Hillebrand and H. S. Washington 298 



XXVI. — The Taconic System of Emmons, and the use of 

 the name Taconic in Geologic nomenclature ; by C. D. 

 Walcott. (With Plate III) 307 



XXVII. — Three Formations of the Middle Atlantic Slope ; 



by W. J. McG-ee 328 



XXVIII. — Diorite Dike at Forest of Dean, Orange County, 



N. Y. ; by J. F. Kemp 331 



XXIX. — New Lecture Apparatus for determination of Re- 

 flection and Refraction; by W. L. Ste'vens . .... 332 



SCIENTIFIC INTELLIGENCE. 



Chemistry and Physics — Spectrum of the Residual Glow, Ckookes, 334. — Pres- 

 ence of Chlorine in Oxygen prepared from Potassium chlorate, Bellamy : 

 Interaction of zinc and sulphuric acid, MuiR and Adie, 335. — Organic Analysis, 

 A. B. Prescott: Practical Physics, B. Stewart and W. W. H. Gee, 336. — • 

 Spectrum of the oxyhydrogen flame, G. T>. Liveixg and J. Dewar : Application 

 of the Electrolysis of Copper to the Measurement of Electric Currents, Gray : 

 Influence of light upon electrical discharges : Wave-lengths of standard lines, 

 F. Kurlbatjm, 337. 



Geology and Natural History. — Distribution of strain in the Earth's crust resulting 

 from secular cooling, 0. Davison and G. H. Darwin, 338. — Lavas of Krakatoa: 

 Geologie von Bayern, K. W. von Gumbel: Recent contributions to our knowl- 

 edge of the vegetable cell, 34 1 . 



Miscellaneous Scientific Intelligence. — Beitrage zur Geophysik, G. Gerlaxd, 344. 

 Klima und Gestaltung der Erdoberfiache in ihrer Wechselwirkung dargestellt 

 von J. Probst : Beobachtungs-Ergebnisse der Norwegischen Polarstation 

 Bossekop in Alten, A. S. Steen : The Asteroids, or Minor Planets between 

 Mars and Jupiter, D. Kirkwood : Manual of Descriptive Geometry, C. A. 

 Waldo, 345. — Annals of the Astronomical Observatory of Harvard College, E. 

 C. Pickering : Movements of the Earth, J. N Lockyer : Publications of the 

 Lick Observatory of the University of California, E. S. Holden: Cordoba 

 Observations : Elementary Treatise on Analytical Mechanics, W. G. Peck, 346. 



Obituary. — James C. Booth, 346. 



