CONTENTS. 



Page. 



Art. XXX. — The Absolute Wave-length of Light ; by Louis 



Bell. Part II 347 



XXXI. — Three Formations of the Middle Atlantic Slope ; 



by W. J. McGee. (With Plates VI and VII) 367 



XXXII. — On some peculiarly spotted Rocks from Pigeon 



Point, Minnesota; by W. S. Bayley 388 



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

 the name Taconic in Geologic nomenclature ; by Chas. 

 D. Walcott 394 



XXXIV. — Terminal Moraines in North Germany ; by Pro- 

 fessor R. D. Salisbury .. 401 



XXXV. — Note on the Viscosity of Gases at High Tempera- 

 tures and on the Pyrometric use of the principle of Vis- 

 cosity ; by Carl Barus 407 



SCIENTIFIC INTELLIGENCE. 



Chemistry and Physics — Boiling-point and molecular formula of Stannous chloride, 

 Biltz and Victor Meter: Occurrence of G-ermanium in Euxenite, Kjtriss, 

 410. — Double Acetate of calcium and copper, Rudorff : Ueber die Reaktions- 

 geschwindigkeit zwischen islandischem Doppelspat und einigen Sauren, W. 

 Spring: Integral Weight of Water, T. S. Hunt, 411. — Absorption Spectra, Fr. 

 Stenger. 412. — Wave-length of the two red lines of potassium: Explosion of 

 gases, A. von CEttingen and A. von Gernet : Dust particles in the Atmos- 

 phere, John Aitkin, 413.— Magnesium and Zinc, Hirn: Gravity, 414. 



Geology and Mineralogy — Geology: Chemical, Physical and Stratigraphical, J. 



Prestwich, 414. — Level-of -no-strain and mountain making : Geology of Rhode 



Island; Franklin Society Report : Annual Report for 1886 of the Geological 

 • Survey of Pennsylvania: Annuaire Geologique universe], Revue de Geologie et 



Paleontologie, 415. — The Geological Record for 1819, W. Whitaker and W. 



H. Dalton : Manual of the Geology of India, Part TV, Mineralogy, F. R. 



Mallet : Brief notes on recently described minerals, 416. — Note on Xanthitane, 



L. G. Eakins, 418. 



Botany and Zoology — Recent contributions to our knowledge of the vegetable cell, 

 Loew and Bokorkt, 419. — Garden and Forest, C. S. Sargent: Bibliotheca 

 Zoologica, 42 0. — Report on the Annelids, of the Dredging Expedition of the U. 

 S. Coast Surrey Steamer " Blake," E. Ehlers, 424. 



Miscellaneous Scientific Intelligence — National Academy of Sciences, 424. 



Obituary — Oscar Harger, 425. — Jules-Emile Planchon, 426. 



