CONTENTS. Vll 



Number 287. 



Page. 



Art. LL — Variations and Mutations; by W. B. Scott 355 



LIL-— An Iodoroetric Method for the Estimation of Telluric 



Acid; by F. A. Gooch and J. Howland 375 



LI II. — Resonance Analysis of Alternating Currents ; by M. 



I. Pupin... 379 



LIV. — Origin of Bitumens. A Retrospect ; by S. F. Peck- 

 ham 389 



LV. — Simple Chronograph Pendulum ; by C. Barus 396 



LVI. — New Methods of obtaining Platinochlorides. Proba- 

 ble Existence of a Platinum Subchloride; by M. C. Lea 397 



LVII.— Study of the Cherts of. Missouri; by E. O. Hovey _ 401 



LVIII — Qualitative Separation of Chromium from Iron and 



Aluminium; by R. B. Riggs 409 



LIX. — Copper Crystals in Aventurine Glass ; by H. S. 



Washington 411 



LX.— Cassium-Cobalt and Caesium-Nickel Double Chlorides, 



Bromides and Iodides ; by G. F. Campbell 418 



SCIENTIFIC INTELLIGENCE. 



Chemistry and Physics — Electric Conductivity of Cases, Braun: Connection 

 between the Atomic masses of metals and the Crystal! ographic characters of 

 their Isomorphous salts. Tittton, 421. — Influence of Moisture on Chemical 

 Change Bakkr. 422. — Production of free Fluorine by Chemical means, Brauner, 

 423. — Structure of the Flame of Cyanogen, Smithells and Dent. 424. — Select 

 Methods in Chemical Analysis, Crookes: Elementary Manual of Chemistry. F. 

 H. Storer and W. B. Lindsay. 425. — Movements of the Solar Atmosphere. M. 

 H. Peslandres: Luminous effects produced by electric oscillation. LL Ebert: 

 Resistance of Bismuth in strong magnetic fields, H. J. B. Henderson, 427. — 

 Motion of dielectric bodies in a homogeneous electrostatic field. Le Graetz and 

 L. Fomm: Maxim's flying machine, H. S. Maxim: Treastise on the Measure- 

 ment of Electrical Resistance, W. A. Price, 428. — Practical Work in General 

 Physics, W. G. Woollcombe, 429. 



Geology and Mineralogy — Occurrence of Anorthite and Epidote, F. W. Clarke: 

 New locality of true Emeralds, G. F. Kuxz, 429. — Physical Geology and Geog- 

 raphy of Great Britain, by the late Sir Andrew 0. Ramsay: Story of our Planet, 

 T. G. Bonney, 430. 



Botany — Flora of Mt. Desert Island, Me., E. L. Rand and J. H. Redfield: Re- 

 searches in regard to the respiration of Muscineas, B. Jonsson: Constitution of 

 the Atmosphere, T. L. Phipson, 431. 



Astronomy and Mathematics — Collected Mathematical papers of Henry John 

 Stephen Smith: Cordoba Durchmusterung Atlas, 432. 



Miscellaneous Scientific Intelligence — Popular lectures and addresses, Sir TV. 

 Thomson (Baron Kelvin): International Geological Congress, 433. — Chloride 

 of mercury batteries, D. H. Fitch, 434. 



