March 6, 1879] 



NATURE 



CXXXiX 



DUNHEVED COLLEGE (LIMITED), 



LAUXCESTON, CORNWALL. 

 Seven hours from London. Separate Bedrooms. Systematie Teaching 

 in Science, Foreign Languages, and University Courses. 

 Calendar post free from 



The Principal— benjamin RALPH. LL.B. Dub. 



ROYAL POLYTECHNIC— CLASSES for 



the preparation of Students for University Examinations, under the 

 direction of EDWARD B. AVELING, D.Sc, F.L.S. London Uni- 

 versity Matriculation, ist and 2nd B.Sc, Preliminary Scientific M.B., 

 Botany, Physiology, Chemistry. All the work practical. 



BERNERS COLLEGE.— The Laboratory 



and Class Rooms are open for Private and Class Study, morning and 

 evening. ANALYSES performed. Especial arrangements for Gentle- 

 men and Ladies preparing for the various Examining Boards. Fees 

 moderate. — Apply to ProC Gardner, at Bemers College, 44, Bemers 

 Street. W. 



THIN GLASS FOR MICROSCOPIC 



MOUNTING, of best quality. Cy'cles, y. td. per ounce ; Squares, 

 2j. ijd. ; post free id. extra ; Grouna edged Slips, SJ. per gross ; also 

 other Mounting Materials and Objects prepared for mounting.— CH AS. 

 PETIT, 151, High Street. Stoke Newington, N. 



DIAMONDS IN MATRIX. 



R. C. NOCKOLD, Diamond and Oriental Stone Cutter and Dealer, has 

 for sale specimens of the above ; also Cut Precious Stones in all Colours. 

 12, FRITH STREET, SOHO, W. 



HOW to MAKE a TELESCOPE, a MICRO- 



SCOPE, and a MAGIC LANTERN. How to TAKE a PHOTO- 

 GRAPH and PRINT a CARTE, see ILLUSTRATED CATALOGUE, 

 now ready, 3 stamps. Containing full direction for above, and how to 

 TRANSFER LANTERN SLIDES. 



J. L.AN CASTER & SON, Bull Street, Birmingham. 



The LANCASTER ELECTRIC LAMP, de- 



vised by W. J. LANCASTER, F.C.S., F.R.A.S., Sc, in three sizes. 

 No. I, to bum 3 hours, £,1 2s. ; No. 2, to bum 6 hours, £^ y. ; largest 

 size, £5 $s. Set of 20 Quart Bunsen's Cells, £4 45. Model Electric 

 Lamp and 10 Cells, £2 12s. 6d. 



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C O 



GENERAL ADVERTISING OFFICES, 



78, GRACECHURCH STREET, LONDON, E.C. 



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ESTABLISHED 1846. 



Advertisements of every description received for insertion in all News- 

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Estimates for General Advertising. Reduction for a series. 



Liberal terms to large advertisers. 



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

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C. H. MAY & CO., having special communication with the leading news- 

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The Press Manual, containing a complete List of Newspapers published 

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MINERALOGY AND GEOLOGY. 



24 assorted Minerals for Blowpipe Experiments, with printed List, in 

 Pocket Case, 2s. ; 24 ditto (second series), 2s. ; Moh's Scale of Hardness 

 of Minerals, 9 Specimens with File and streak tablet in a convenient Case, 

 4s. ; von Kohbell's Scale of Fusibility of Minerals, 6 Specimens in Pocket 

 Case, 2S. ; Geological CoUecdag Bag complete, +1. ; Ditto Hammer 

 Holder and Strap, 2s. Geological Charts, Bool^ Hammers, Chisels, 

 Lenses, Acid Bottles, Glass-capped Boxes, Cement for Moundng and Re- 

 pairing Fossils, Tablets, Card Trays, &c., &c. Minerals, Fossils, and 

 Rocks, sent on approval and for selection to all parts of the world. 



THOMAS J. DOWNING, 



38, WHISKIN STREET. LONDON, E.C. 



CATALOGimS FREE. 



SHEPPEY FOSSILS. 



W. H. SHRUBSOLE, Shberness-on-Sea, respectfully intimates that 

 the appeal recently made by him has been so heartily responded to, that he 

 cannot receive any more orders for " extra selected " specimens at present. 



Orders for loj. Collections of 100 " good " specimens can be executed 

 without delay. 



" NOTES ON THE GEOLOGY OF SHEPPEY " post fre« on appU- 

 cation. 



WANTED, Clean Copies of NATURE, 



Na 35S and 433. — ^AddressJ Office o£ NATtniK, 29, Bedford Street, 



Strand. t 



ELECTRICAL & SCIENTIFIC APPARA- 

 TUS for AMATEURS and the TRADE.— Microph:)nes of every form, 

 from IS. 6d. New cheap Electric Lamps and Batteries. Induction 

 Coils and Frictional Machines are specialties. Electrical Bells, Fire 

 and Thief Alarms, and Automatic Switch-boards. Magnets, Covered 

 Wires, Screws, and all Materials. Apparatus for Science Teachers. 

 Illustrated Catalogue, one stamp. Repairs and Alterations. Appara. 

 tus made to sketch.— D.ALE & CRAMPTON, Manufacturing Elec- 

 tricians, 4, Little Britain, E.G. 



GEOLOGY In the Preface to the Student's 



ELEMENTS of GEOLOGY, by Sir Charles Lyell, price 9*., he says : 

 — "As it is impossible to enable the reader to recognise rocks and mioe- 

 rals at sight by aid of verbal descriptions or figures, he will do well to 

 obtain a well arranged collection of specimens, such as may be procured 

 from Mr. TEN N ANT (149, Strand), Teacher of .Mineralogy at Kinjg's 

 College, London." These Collections are supplied oa ue followiiK 

 terms, in plain Mahogany Cabinets : — 



100 Specimens, in Cabinet, with 3 Trays ......... £2 a o 



200 Specimens, in Cabinet, with 5 Trays ......>.. 5 5 o 



300 Specimens, in Cabinet, with 9 Drawers ... m. 10 10 O 



400 Specimens, in Cabinet, with 13 Drawers ~. ~< 21 o o 



More extensiva Collections at 50 to 5,000 Guineas each. 



MINERALOGY AND GEOLOGY. 



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

 including Special Collections to illustrate the various Text-books, in 

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

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

 Geological Hammers, with prices. List of New and Second-hand Books of 



JAMES R. GREGORY, 



MUSEUM OF GEOLOGY. 



88, CHARLOTTE STREET, FITZROY SQUARE. 

 THE 



^5 ASTRONOMICAL TELESCOPE 



HAS A 3-INCH OBJECT-GLASS. 



Which shows the Ring of Saturn, Belts of Jupiter, and separates the 



principal Double Stars. 



S. & B. SOLOMONS, 



61, PALL MALL, 

 OPPOSITE M.ARLBOROUGH HOUSE. 



THE ENTOMOLOGIST'S MONTHLY 

 MAGAZINE. 



Price Sixpence, Monthly, 24 pages 8vo, with occaaonal Illustnitions. 



Conduaed by J. W. Douglas, R. McLachlan, F.R.S., E. C. Rye, F.Z.S. 



and H. T. Stainton, F.R.S. 



This Magazine, commenced in 1864, contains standard articles and note 



on all subjects connected with Entomology and especially on the Insects of 



the British Isles. 



Subscription — Six Shillings per Volume, post free. The volumes com- 

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Vols. I. to V. (strongly bound in cloth) may be obtained by purchasers of 

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London: JOHN VAN VOORST, i. Paternoster Row. 

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THE BEST FARMER S' NEWSPAPER. 



THE CHAMBER OF 

 AGRICULTURE JOURNAL 



AND FARMERS' CHRONICLE, 



Edited by John Auskrsou Clarke, Secretary to the Central Chamber 



of Agriculture, 

 Devote* special attention to the discussions and proceedings of the Chamber 

 of Agriculture of Great Britain (which now number upwards of 18,000 

 members), besides giving original papers on practical farming, and a mass of 

 intelligence of particular value to the agriculturist. 



The London Com, Seed, Hop, Cattle, and other Markets of Monday arm 

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Published by W. PICKERING 21, Arundel Street, Strand, W.C 



THE "HANSA," 



Published since i8€4, in Hamburg, is the only independent professional 

 paper in Germany, dedicated exclusively to Maritime Objects. Essays, 

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 Office : Aug. Meyer and DiecVmann, Hamburg, Alterwall, 28. Edited by 

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