CONTENTS. Vll 



Number 215. 



Page 



Art. XXXIII. — Deflection of the Plumb-line and Variations 



of Gravity in the Hawaiian Islands ; by E. D. Preston, 305 



XXXIV.— Mineralogical Notes; by S. L. Penfield and E. 



S. Sperrt 317 



XXXV. — Absorption Spectra of certain Blue Solutions ; by 



F. B. Pitcher _ 332 



XXXVI. — Instrument for Demonstrating the Laws of Trans- 

 verse Vibrations of Cords and Wires; by G. S. Moler_ 337 



XXXVII. — Rhaetic Plants from Honduras ; by J. S. New- 

 berry. With Plate VIII 342 



XXXVHI. — Circular Polarization of certain Tartrate Solu- 

 tions ; by J. H. Long _ _ _ 351 



XXXIX. — Energy and Vision ; by S. P. Langley _ _ 359 



XL. — Mineralogical Notes; by W. E. Hidden 380 



SCIENTIFIC INTELLIGENCE. 



Chemistry and Physics. — Eelation of Solubility to Fusibility, Carnelley and 

 Thomson, 383. — Raoult's method for determining Molecular Weights, Raoult, 

 384. — Vapor-density of Hydrofluoric acid, Thorpe and Hamblt: Spectrum of 

 Oxygen, Janssen : Yalence of Oxygen, Hetes, 385. — Carbon Atom and 

 Valence, V. Meter and Riecke, 386. — Chemical Analysis of Iron, A. A. 

 Blair: Interference of Electro-magnetic Waves, Fitzgerald, 387. — Ultra 

 violet Spectra of Metalloids, Deslandres: Substitute for Bisulphide of Car- 

 bon in Optical work, H. G. Madan: Index to the Literature of the Spectro- 

 scope, by A. Tuckerman, 388. 



Geology and Mineralogy. — International Geological Congress at London: Theo- 

 retische Geologie, E. Reter, 389. — Formes du Terrain, Noe and de Margerie : 

 Structure and Classification of the Mesozoic Mammalia, Osborn: Eozoon 

 Canadense, Dawson, 390 — Nya anmarkningar om Williamsonia af A. G. 

 Nathorst: Riebeckite, a new mineral: Mazapilite, a new mineral, 391. — Min- 

 erals of New York County, Chamberlin, 392. 



Botany and Zoology. — Dr. Watson's Contributions to American Botany: Flora of 

 Middlesex County, Mass., Dame and Collins, 392. — Catalogue of Plants grow- 

 ing in Nantucket County, Mass., Owen, 393. — Catalogue of the Flora of Ver- 

 mont, Perkins: Plants of Rhode Island, Bennett, 394. — Catalogue of Flower- 

 ing and Fern-like Plants growing in vicinity of Niagara Falls, Day : Journal of 

 Morphology, 395. 



Miscellaneous Scientific Intelligence. — Meeting of the British Association at Bath in 

 1888. 



Obituary. — Benjamin B. Chamberlin, 396. 



