CON DENTS. 



Number 258. 



Page 



Art. LVIII. — Subdivisions in Archaean History; by J. D. 



Dana . 455 



L1X. — Electrical Discharges through poor Vacua, and on 

 Coronoidal Discharges; by M. I. Pupin. With Plate 

 XIV 463 



LX. — Rubidium and Potassium Trihalides; by H. L. Wells 

 and IT. L. Wheeler. With their Crystallography ; by 

 S. L. Penfield 475 



LXL— Clinton Iron Ore ; by C. H. Smyth, Jr 487 



LXII.— Wilde's Explication of the Secular Variation Phe- 

 nomenon of Terrestrial Magnetism; by L. A. Bauer.. 496 



LXIII. — Josephinite, a new Nickel-Iron; by W. H. Mel- 

 ville •_ 509 



LXIV. — Fibrous Intergrowth of Augite and Plagioclase, re- 

 sembling a reaction rim, in a Minnesota Gabbro ; by W. 

 S. Batle y 515 



LXV. — Method for the Determination of Barium in the pres- 

 ence of Calcium and Magnesium ; by F. W. Mar 521 



LXVI. — Note on the Absorption of Radiant Heat by Alum ; 



by C. C. Hutchins 526 



LXVIL— Disruption of the Silver Haloid Molecule by Me- 

 chanical Force ; by M. Carey Lea 527 



Appendix. — LXVIII. — Notes on Triassic Dinosauria ; by O. 



C. Marsh. With Plates XV, XVI, and XVII 543 



SCIENTIFIC INTELLIGENCE. 



Chemistry and Physics. — Polarization of Platinum by Oxygen and Hydrogen, 

 Markofskt, 531. — Basicity of Phosphoric Acid, D. Berthelot, 532.— Occlu- 

 sion of Hydrogen by Lead and other metals, Newmann and Streintz: Princi- 

 ples of Chemistry, D. Mendeleeff, 533. — Manual of Chemical Technology, by 

 Rudolf von Wagner, W. Crookes and P. Eischer : Laboratory of Chemistry. 

 J. E. Armstrong and J. H. Norton, 535. — Untersuchungen uber die Aus- 

 breitung der elektrischen Kraft, H. Hertz, 335. — Vorlesugen iiber Maxwell's 

 Theorie der Elektricitat und des Lichtes, L. Boltzmann, 536. 



Geology and Natural History. — A Summary Description of the Geology of Penn- 

 sylvania, J. P. Lesley, 536. — Fossil Botany, H. Graf zu Solms-Laubace and 

 H. E. F. Garnsey and I. Bayley, 537. — Ueber einige carbone Pflanzenreste 

 aus der Argentinischen Repubhk, L. Szajnocha: Cambrian of Sardinia, J. G. 

 Bornemann, 538. — Fossils in the St. Peter's Sandstone, F. W. Sandeson: Cor- 

 relation Papers, W. B. Clark: Glacier Rock-crushing, W. G. Tight: System 

 of Mineralogy of J. D. Dana, E. S. Dana, 539. — Supposed occurrence of Plati- 

 num in North Carolina, F. P. Venable: Summary of Progress in Mineralogy 

 and Petrography, W. S. Bayley : Gay-lussite from San Bernardino Co., Cal., 

 H. G. Hanks, 540. 



Miscellaneous Scientific Intelligence. — Report of the Smithsonian Institution for 

 1890, 540. — Boston Society of Natural History: Proceedings of the Colorado 

 Scientific Society, 541. — Volcano of Kilauea, Hawaii: Physiography, J. Spen- 

 cer: Universal English-German and German-English Dictionary, F. Flugel: 

 The Ward Collection of Meteorites, 542. 



