June 19, 1879] 



NATURE 



lix 



Mr. TENNANT, F.G.S., Professor of 



Mineralogy and Geology, Mineralogist by Appointment to Her Majesty 

 and the Baroness Eurdett-Coutts, 149, Strand, London. W.C., having 

 been fifty years in business, contemplates shortly RETIRING, and 

 offers for SALE several of his extensive COLLECTIONS of Minerals, 

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MINERALOGY AND GEOLOGY. 



A New List of Collections of Fossils, Minerals, and Rocks now ready, 

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 JAMES R. GREGORY, 

 MUSEUM OF GEOLOGY. 



88, CHARLOTTE STREET, FITZROY SQUARE. 



MINERALOGY. 



COLLECTIONS FOR STUDENTS FROM 41.— SINGLE SPECI- 

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FINE SIBERIAN MINERALS. 

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JOURNAL OF THE SOCIETY OF 

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No. 27, Vol. VIII. SPECIAL NUMBER. 

 Edited by W. E. Ayrton, containing a Paper with Illustrations on — 



Some Historical Notes on the Electric Light. By Lieut. -Col. Bolton, Hon 

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Also Illustrated Papers on — 



Experimental Researches into Means of Preventing Induction upon Lateral 

 Wires. Prof. D. E. Hughes. 



South African Telegraphs. By Sive Wright, M.A. 



Notes on Earth-Currents. By W. Ellis, K.R.A.S. 



The Electromotive Force of Mercury Alloys. By C. Hockin, M.A., and 

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