CONTENTS. 
Art. XX.—On the Absolute Wave-length of Light; by 
Louis, Baul So s282 oon 0 ee 
XXI—On the Relative Wavelength of the Lines of the 
Solar Spectrum; by Henry A. RowLanp_.---.---~--- 
XXII—The Norites of the ‘“‘ Cortlandt Series” on the Hud- 
son River near Peekskill, N. Y.; by G. H. WriziaMs -. 
XXIII.—Natural solutions of Cinnabar, Gold and associated 
sulphides’; = by GrorcE I’. .BECKER —22: 222 eon aes 
XXIV.—Fluviatile Swamps of New England; by N. 8. 
SHATER Soe 2 See ey ee See 22 oo 23 es eee 
XXV.—On the Mazapil Meteoric-iron, which fell November 
27th, 1885; by Wittiam Har HIppEen -- 2-22-2223 
XXVI.—On Observations of the Eclipse of 1887, Aug. 18, 
in connection with the Electric Telegraph; by Davip 
P2Topp sss ae Bel See pee SS Se a 
XXVII.—On the new Meteorites from Carroll County, Ken- 
tucky, and Catorze, Mexico; by Grorer F. Kunz----- 
SCIENTIFIC INTELLIGENCE. 
Chemistry and Physics.—Production of Fluorine by the electrolysis of Hydrogen 
Fluoride, MoIssANn, 236.— Methods of avoiding errors due to polarization, in the 
use of double image prisms: Electromotive force due to the Voltaic are, LEO, 
ARONS, 237.—Generalization of the Wheatstone Bridge, O. FROHLICH: A nearly 
perfect simple pendulum, J. T. BorromiEy: Acoustical Investigations, F. 
MELDE, 238. 
Geology and Mineralogy.—Kilauea, 239.—Origin of Mountain Ranges considered 
experimentally, structurally, dynamically and in relation to their Geological 
History, T. MELLARD READE, 240.—Skeleton of a Whale found over 130 years 
since in the St. Lawrence River Valley, near Quebec: Geological History of 
Lake Labontan, a Quaternary Lake of Northern Nevada, IsRAnL Cook 
Rovs- 
SELL: Geographical and Geological Distribution of Animals, ANGELO HEILPRIN, 
242.—Manual of Mineralogy and Lithology, J. D. Dana: Chemical composition 
of the orthoclase in the Cortlandt Norite, G. H. Winuiams, 248.— Nickeliferous 
metallic Iron from New Zealand, Uuricu, 244. 
Botany and Zoology.—Minor Botanical Notes, 244.—Bibliotheca Zoologica IT, 
O. TASCHENBERG, 245. - 
Miscellaneous Scientific Intelligence—The American Naturalist:. The Swiss Cross, 
a Monthly Magazine of the Agassiz Associations, 246. 
