CONTENTS. 



Number 33. 



Page 



Art. XX. — Transition Temperature of Sodic Sulphate, a 



New Fixed Point in Thermometry ; by T. W. Richards 201 



XXI. — Distribution and Quantitative Occurrence of Vana- 

 dium and Molybdenum in Rocks of the United States; 

 by W. F. Hillebrani> _.. 209 



XXII.— Electrosynthesis ; by W. G-. Mixter 21 



XXIII. — Notes on Species of Ichthyodectes, including the 

 new species I. cruentus, and on the related and herein 

 established genus Gillicus; by O. P. Hay 225 



XXIV. — Determination of Manganese as the Pyrophosphate; 



by F. A. Gooch and M. Austin 233 



XXV. — Occurrence of Dunite in Western Massachusetts; 



by G. "C. Martin 244 



XXVI. — Origin and Significance of Spines : A Study in Evo- 

 lution ; by C. E. Beecher 249 



SCIENTIFIC INTELLIGENCE. 



Chemistry and Physics — Laboratory Guide in Qualitative Chemical Analysis, H. 

 L. Wells: Short Course in Inorganic Qualitative Analysis for Engineering 

 Students, J. S. C. "Wells: Introduction to Electro-chemical Experiments, F. 

 Oettel, 209. — Remarks on Colloidal Glass, C. Barcs, 270. 



Geology and Mineralogy — Late Formations and Great Changes of Level in 

 Jamaica, J. W. Spencer, 270. — Resemblance between the Declivities of High 

 Plateaus and those of Submarine Antillean Valleys, J. W. Spencer, 272. — 

 Eruptivgesteine des Kristianiagebietes, Part III, W. C. Brogger, 273. — Bad- 

 deckite, a new variety of Muscovite, G. C. Hoffmann. 274. — Text Book of 

 Mineralogv with an extended Treatise on Crystallography and Physical Miner- 

 alogy, E. S. Dana, 275.— L'or dans la Nature, R. Cumenge and F. Robellaz, 

 276. 



Botany — Illustrated Flora of the Northern States and Canada, N. L. Britton 

 and Addison Brown, 277. 



Obituary — Professor James Hall, 284. 



