June 26, 1879] 



NATURE 



Ixvii 



Mr. TEN N ANT, F.G.S., Professor of 



Mineralogy and Geulogy, Mineralogist by Appointment to Her Majesty 

 and the Uaroness Burdett-Coutts, 149, Strand, London. W.C., having 

 teen fifty years in business, contemplates shortly RKTIRING, and 

 offers for SALE several of his extensive COLLLCTItJNS of Minerals, 

 Rocks, and Fossils. They are well adapted for first-class Educational 

 Establishments, Provincial ur Colonial Museums, or for the Private 

 Study of any Scientific Person wishing to become acquainted with the 

 above-mentioned Sciences. From ^1,000 to 5,000 Guineas. Students' 

 Collections at 2, 5, 10, 20, to 50 Guineas. 



MINERALOGY AND GEOLOGY. 



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

 includmg Special Collections to illustrate the variuus Text-books, in 

 Cabinets. List of Sections t f Rocks for the Microscope Blowpipe Appa- 

 ratus ard Materials of all kinds in Cases or separately. New Patterns of 

 Geological Hammers, with prices. List of N«w and Second-hand Books of 



JAMES R. GREGORY, 



MUSEUM OF GEOLOGY, 



88, CHARLOTTE STREET, FITZRDY SQUARE. 

 MINERALS. ROCKS, AND FOSSILS. 



COLLFXTIONS IN CABINETS. 

 Two Hundred Specimens, t,os. ; 150 do., 30^. ; 100 do., %zs. \ 50 do., xos. 

 Size of Specimens, 2 stjuare inches. Naming and Localities guaranteed. 

 Superi ir Cabinets fitted with Card-Trays and Catalogue included. 

 *"1 he Popular .Scientific Pocket Cabinet Series " comprises 9 Cabinets and 

 224 Specimens. 2J. td. each Cabinet, free delivery, 4*/. (See Nature, 

 March 13. No. 4S9, page 447.) 



The Collector's Field Apparatus compUte, zi'. Hammer-holder and 

 Waist-strap, price is. Collecting-bag (figured and de^cribedj, price 4^. - 

 THOMAS J. DOWNING, Geologist, &c., 

 38, WHSKIIN STREET, LONDON, E.C. 

 Catalogue, Lists, and " Quarterly Circular " free on receipt of 2(/. postage. 



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Advertisements are also received for all newspapers, which may be ad- 

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C. H. MAY & CO., having spcc'al communication with the leading news- 

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 The Press Manual for 1879, containing a complete Lbt of Newspapers 

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LA SEMAINE FRANCAISE : a Weekly 



New?;paper and Review in the French Language. Politics, Literature, 

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LA SEMAINE FRANCAISE: Journal Frangaise pour 



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LA SEMAINE FRANCAISE.— '"La Semaine Fran- 



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 view, instead of confining their reading to cne particular Gallic print. 

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LA SEMAINE FRAN^IAISE.— " Tel est le titre d'un 



journal hebdomadairc, nous pourrioai dire d'une revue de tous les jour- 

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 les ineillcurs articles, politique^ critiques, ct litt^raires, qui ont paru 

 p-^ndant la semaine dans les journaux de Paris. Assurtment le num6ro 

 que nous av'.ns sous les ycux est un excellent specimen de ce que pcut 

 faire un heureux choix, guid6 par une intelligence parfalte de ce qui pcut 

 int^resser Ics lectcurs."— A^(7«z^f//* Chronique dt Jersey, 



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one of the best papers published in Paris itself. We are much nteased 

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JOURNAL OF THE SOCIETY OF 



TELEGRAPH ENGINEERS. 



No. 27, Vol VIIL SPECIAL NUMBER. 

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



Seme Historical Notes on the Electric Light. By Lieut. -Col. Bjlton, Hon 

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 arranged in sub-divisiuns according to the special class feature of each 

 form of machine or lamp. 



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, F.R.A.S. 



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

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MIND, 



A QUARTERLY REVIEW OF PSYCHOLOGY AND PHILOSOPHY. 



No. XV. is now ready, containing Articles by Grant Alien, Prof. Wm. 

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L'ELEGTIUGITE 



RevTio sciontlflquo lllustx-oo 



ParoisstTiit le 5 ot lo 20 de cha((Uo mois 

 En U7iebeUe iivraisDn dn vi nnl-q ualre pages graridinSo Jdsui 



T^Wgraphie. — Galvanoplastio.— MeWorologie.— Medeoiaa 

 Art miljtairs. — Applications divorsea 



OROA.NE SPECIAL DISS I'ROQUSs Dg LA LU.MliiRE ELEOrniQUB 



Publii-ation r^difeo depuis 1876 aveo la collaboration dos 



priiicip'jux eloctnciens franfais et dtrangors. 



Secrilaires do la Rodaotion : W. dk Ko.nvielle et le C'« d'Akros. 



Dirocteur : E. he Clisso.n. 



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WANTED, Clean Copies of NATURE, No. 472, 

 for Nn<ember 14, 1878. Address — Office of 

 NATURE, 29, Bedford Street, Strand. 



