iv CONTENTS. 



Number 254. 



Page 



Art. XII.— I'm of a Free Pendulum as a Time Standard; 



by T. C. Mbndenhali 85 



XIII. — Bear River Formation, a Series of Strata hitherto 



known as the Bear River Laramie; by C. A. White 91 



XIV. — Stratigraphic Position of the Bear River Formation ; 



by T. W. Stanton 98 



XV. — Iron Ores of the Marquette District of Michigan; by 



C. R. Van Hise 116 



XVI. — Illustration of the Flexibility of Limestone; by A. 



Winslo w 133 



XVII. — Separation of Iron, Manganese and Calcium by the 



Acetate and Bromine Methods; by R. B. Riggs 135 



XVIII. —Central Massachusetts Moraine ; by R. S. Tarr__ 141 

 XIX. — Proofs that the Holyoke and Deerfield Trap Sheets 



are Contemporaneous Flows and not later intrusions; 



by B. K. Emerson . 146 



SCIENTIFIC INTELLIGENCE. 



Chemistry and Physics — On the Gravi-volumeter, Japp: The element fluorine, 

 MoiSSAN, 149. — Commercial production of Ozone, Frolich, 150. — Free Hy- 

 droxylamine. Lobry deBruyn: Iron Carbonyls. Mond and Danger, 151. — 

 Presence of Iron-Carbonyl in Water Gas, Roscoe and Scubder: An Introduc- 

 tion to Chemical Theorj T . A. Scott, 152. — Experiments arranged for Students 

 in General Chemistry, E. F. Smith and H. F. Keller: Text-book of Element- 

 ary Chemistry, G. F. Barker: Low Temperatures, Pictet, 153 — Vibrations of 

 Strings, Menzel and Raps, 154. — The Telephone as an optical instrument for 

 current measure, M. Wien: Solubility of Glass, F. Kohlrausch: Introduction 

 to the Mathematical Theory of Electricity and Magnetism, W. T. A. Emtage, 155. 



Geology and Mineralogy — Tenth Annual Report of the U. S. Geological Survey, 

 1888-89, J. W. Powell, Director, 155.— Stratigraphy of the Bituminous Coal 

 Field of Pennsylvania, Ohio aud West Virginia, I. C. White, 156. — Age of the 

 Plants of the American Trias, L. F. Ward : Chalk and flints at the Solomon 

 Islands, Liveesidge, 15*7. — Paramelaconito and Footeite, G. A. Koenig: Notes 

 on the Genus Acidaspis, etc., J. M. Clarke, 15S.-^Cretaceous fossils of Syria: 

 Igneous Rocks of Arkansas, J. F. Williams, 159. 



Bol any and Zoology — Specific Assimilation in Umbelliferse, de Lamarliere, 160. 

 — Effects of poisons on the germination of seeds, Oh. Gornevin : Proofs of 

 land-communication between Europe and America during the "modern" age of 

 the earth, E. Blanchard: Comparative Anatomy of Plants. Ad. Chatin, 161. 

 — Experiments on Root-grafting, L. Daniel : Physiological notes : Die natiir- 

 lichen Pflanzenfamilien, Engler and Prantl: Work of the Lobworms in bring- 

 ing Sand to the Surface, C. Davison, 162. 



Astronomy and Terrestrial Physics — Periodic Variation of Latitude, 163. — Astron- 

 omy and Astro-Physics, 166. 



Miscellaneous Scientific Intelligence — Essays upon Heredity and kindred Biological 

 Problems, A. Weissmann : Ostwald's Klassiker der exakten Wissenschaften : 

 Minerals, A monthly magazine, 166. — Modern American Methods of Copper 

 Smelting, E. D. Peters, Jr., 167. 



Obituary — Dr. Joseph Lovering: William P. Rust, 167. — Sir Andrew Crombie 

 Ramsay: Dr. Ferdinand von Rcemer, 168. 



