Augusi 7, 1879] 



NA TURE 



CXVll 



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 To the Colonies, United States, 

 all places within the Postal Union 



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 7s. 6d. 

 the Continent, and 



3w. 



IS J. 

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6d. 



6d. 



Office : 29, Bedford Street, Strand. 



W. LADD & CO., 



Scientific Instrument Manufacturers 



{By Appptnimtni to the Royal Institution of Great Britain^ 



11 & 12, BEAK STREET, REGENT STREET, W. 



BYRNE'S PATENT COMPOUND PLATE PNEU- 

 MATIC BATTERY for Cautery and general purposes. 



EDMUNDS' PHONOSCOPE for making Vocal Vibra- 

 tions visible in a Vacuum Tube. 



HUGHES' MICROPHONE. 



TELEPHONIC APPARATUS, Ac. 



LADD'S IMPROVED SELF CHARGING HOLTZ 

 ELECTRICAL MACHINE, witli 4 to 12 Plates, in- 

 closed in a Mahogany and Glass Case. This instrument is 

 immediately available in any condition of the atmosphere. 

 Philosophical Apparatus of every Description. 



Illustraied Catalogue, Sixpenet, 



EUDOLPH KOENIG, 



(DR. PHIL.) 

 MANUFACTURER OF 



ACOUSTICAL INSTRUMENTS. 



TO ILLUSTRATE THE LAWS 



AND TO PRODUCE THE PHENOMENA OF SOUND. 



PARIS, 26, EUE DE PONTOISE. 



PRICE LISTS FREE. 

 Now ready, a Revised Edition, 



NEGRETTI & ZAMBRA'S 



encyclop.s;dic 

 Illustrated, and Descriptive 



CATALOGUE OF 



SCIENTIFIC INSTRUMENTS. 



(CoMtaining very numeroui Comparative Tables of Reference and 



lilu.'^tratcd by upwards of TWELVE HUNDRED ENGRAVINGS. 



Six Hundred Pagc5, Royal 8vo, cloth, gilt lettered, Price 5J. (xi.) 



Optica], Mathematical, Philosophical, Photographic, 



AND 



STANDARD METEOROLOGICAL 

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MANUFACTURED AND SOLD BY 



NEGRETTI AND ZAMBRA, 



Opticians and Scientific Instninient Makers to 



The RoT*10b«ervatory, Greenwich; the Admiralty; Hon. Board of Ordnance; 



Board of Trade ; the British Meteurological Society; the Obsenraloiies 



Kew» Toronto, Washington, Victoria ; East Inc&ui Government. 



HOLBORN VIADUCT, E.C. 



ALSO AT 



46, CORNHILL, E.G., & 122, REGENT STREET, W., 

 LONDON. 



ADVERTISING. 

 C . H . MAY <& CO., 



GENER.\L 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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Estimntes for General Advertising. Reduction for a series. 



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

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

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The PresftSlanual for 1B79, containing a complete List of Newspapers 

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FRTS 



COCOA 



GOLD MEDAL,. 

 PARIS EXHIBITION. 



In Packets and Tins. Pure 

 Cocoa only, with the super- 

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EXTRACT 



'* If properly prepared, there is no nicer 

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 edited hy Dr. Hassaii. 



J. S. FRY & SONS, Bristol and London. 

 EAGLE INSURANCE COMPANY, 



79, PALL MALL. 

 F6r Lives only. Estabhshkd itof. 

 Net FremiumB and Interest »..«».».»•». ;£396,8i8 

 Accumulated Funds .«.^».».k.«.».» ;£3,oS3,38i 

 Also a Subscribed Capital of more than. .. .« «- ... Zi, 500,000 

 Reports, Prospectuses, and Forms may be had at the Office, or from any 

 of tlxe Company s Agents, post free. 



GEORGE HUMPHREYS, Actuary and Secntary. 



HOENE'S POMPEIAN DECORATIONS. 



ROBERT HORNE, 



HOUSE DECORATOR and PAPER-HANGING 



MANUFACTURER, 



41, GRACECHURCH STREET, LONDON, E.C. 



By Special Appointment to His Majesty the King of Italy. 



NOW READY, 

 SECOND EDITION, 



G R I F F I N'S 



CHEMICAL HANDICRAFT. 



PRICE 4S. td. POST FREE. 



A CATALOGUE OF CHEMICAL APPARATUS; 



ILLUSTRATED, CLASSIFIED, DESCRIPTIVE. 



Demy 8vo, 480 pp.. Illustrated with i,foo Woodcuts. 



Mtst Compute and Cheapest List of Apparmtm. 



JOHN J. GRIFFIN and SON.S, 22, GARRICK STREET, 

 LONDON, W.C. 



LIGHTNING CONDUCTORS. 



Kxpcrience, accumulated since the tim* o£ Benjamin Franklb, provej 

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 destructive efiocts o£ Ufthtninf. 



NEWALL & CO.'S 



PATENT COPPER LIGHTNING CONDUCTOR, 



As a^Jlied to all kinds of Buildings and Shipping in all parts of the world 

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It is simple in ita a- ;»lica . .., no insulators being required, a-rt t costi 

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 B. S. NBWAI.I< • CO., 130, .Sl'KAND, W.C 



36, WATKRI.dO ROAD, LIVE POOL, 

 68. ANIJURSTON QUAY, C;l,A>GOW. 

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