﻿IV CONTENTS. 



NUMBER CLXXXVIII. 



Page. 



Art. IX. — On hitherto unrecognized Wave-lengths ; by 



S. P. Langley 83 



X. — On the chemical composition of Herderite and Beryl, 

 with note on the precipitation of aluminum and separa- 

 tion of beryllium and aluminum ; by S. L. Peneield 

 and D. N. Harper 107 



XL — Communications from the U. S. Geological Survey, 

 Division of the Rocky Mountains. VIII. On Ptilolite, 

 a new Mineral ; by W. Cross and L. G. Eakins 117 



XII. — Notes on the Peridotite of Elliot County, Kentucky ; 



by J. S. Diller 121 



XIII. — Temperature Observations at the Lake Superior 



Copper Mines ; by H. A. Wheeler 125 



XIV. — An Application of the Copper Reduction Test to the 

 Quantitative Determination of Arsenic; by H. Car- 

 michael . ._. 129 



XV.— On the Crystallization of Gold; by E. S. Dana. . ._ 132 



XVI. — Classification of the Cambrian System of North 



America ; by C. D. Walcott 138 



XVIL— Note on the Spectrum of Comet C, 1886 ; by O. T. 



Sherman 157 



SCIENTIFIC INTELLIGENCE. 



Chemistry and Physics. — On the Combustion of Carbon monoxide and Oxygen, 

 L. Meyer, 159. — On the Combustion of Cyanogen, Dixon: On the so-called 

 Critical Pressure in Solids, v. Richter, 160. — Studies from ihe Laboratory of 

 Physiological Chemistry, Sheffield Scientific School of Yale College, for the 

 Year 1884-85, Chittenden, 161. 



Geology and Natural History. — Geological Survey of Pennsylvania, Lesley : Vol- 

 canic Eruption in New Zealand, 162. — New Minerals, A. Weisbach, 163. 

 The Zoetrope applied to crystallographic transformations, R. H. Richards: 

 Sketch of the Flora of South Africa, H. Bolus, 164. — Descriptive Catalogue of 

 the Gallery of Marianne -North's Paintings of Plants and their Homes, Royal 

 Gardens, Kew, W. B. Hemsley : Official Guide to the Museums of Economic 

 Botany, Royal Gardens, Kew: Filippo Parlatore, Flora Italiana, T. Caruel, 

 165. — Flora Brasilien sis, Schumann: Hooker's Icones Plantarum, 166. 



