IV CONTENTS. 



Number 2. 



Page 



Art. XI — Researches in Acoustics ; by A. M. Mayer 81 



XII. — Improbability of Finding Isolated Shoals in the Open 

 Sea by Sailing over the Geographical Positions in which 

 they are Charted ; by G. W. Littleh ales 1 06 



XIII. — Notes on Sperrylite; by T. L. Walker 110 



XIY. — Glaciation of Pocono Knob and Mounts Ararat and 



Sugar Loaf, Pennsylvania ; by H. B. KtImmel 113 



XV. — Counter-twisted Curl Aneroid ; by C. Bartjs 115 



XVI. — Fayalite from Rockport, Mass., and on the Optical 

 Properties of the Chrysolite-Fayalite Group and of 

 Monticellite ; by S. L. Penfield and E. H. Forbes .. 129 



SCIENTIFIC INTELLIGENCE. 



Chemistry and Physics — Recent investigations on hydrogen peroxide, Traube 

 and Wolffenstein, 136. — Constitution of water and the cause of its power of 

 dissociation, Bruhl: Action of prolonged, moderate heating upon detonating 

 gas, V. Meyer and W. Raum: Absorption of nitrogen by metallic lithium in 

 the cold, H. Peslandres, 138. — Decomposition of silicates by boric acid, P. 

 Jannasch and H. Heidenreich: Lighting: Movable Light phenomena in rari- 

 fied gases occasioned by Electrical oscillations, J. Elster and H. G-eitel, 139. 

 — Ratio between the Electrostatic and Electromagnetic units, M. P. Hurmtt- 

 zesca : Discharges of Electricity through Gases : Pouble Refraction of Electric 

 Waves, R. Mack: Relation between the atom and the charge of Electricity 

 carried by it, J. J. Thomson, 140. — Puration of Electrical Shadows with solid 

 and fluid insulators: Laboratory Course of Experimental Physics, W. J. 

 Loudon and J. C. McLennan: Terrestrial Magnetism, 141. 



Geology and Mineralogy — U. S. Geological Survey, 16th Annual Report, 142. — 

 Recent Publications of the U. S. Geological Survey, 144. — Geology of the 

 Green Mountains in Massachusetts, R. Pumpelly, J. E. Wolff, T. N. Pale, 

 146 — Geological Society of America, 147. — Cerillos Coal Field, J. J. Stevenson, 

 148. — Trap Rock of the Palisades, B. S. Lyman: Missouri Geological Survey: 

 Iowa Geological Survey, 149. — Illinois State Museum of Natural History. S. A. 

 Miller and W. P. E. Gitrley : Geological Survey of Canada : Needed Term in 

 Petrography, L. V. Pirsson: Manual of Lithology, E. H. Williams, 150. — 

 Handbuch der Mineralchemie, C. F. Rammelsberg, 151. 



Botany — Plant-breeding, L. H. Bailey : Tubercles on the roots of the Soja bean, 

 Kirchner, 151. — Modifications of the Cell-wall, Van Wisselingh and Mangin: 

 Accumulation of Sugar in the root of the Beet, L. Maquenne, 152. — Guide to 

 the British Mycetozoa, A. Lister: Norwegian Forms of Lithothamnion, M. 

 Foslie, 153. 



Miscellaneous Scientific Intelligence — Composition of expired air and its effect 

 upon animal life, J. S. Billings, S. W. Mitchell and P. H. Bergey, 154. — 

 Report of the Agricultural Experiment Stations of the University of California, 

 158. — Park companion to one of the components of the binary star 70 Ophiuchi : 

 Books and Pamphlets recently received, 159. 



