CXVIU 



NATURE 



\_A%igtist 7, 1879 



PROFESSOR HUGHES' AUDIOMETER. 



The only perfect measurer for testing the hearing power. Vide DR. RICHARDSON'S Report to the Royal Society, 

 May 15, 1879 ; Medical Times and Gazette, May 24, 1879. 



SOLE AUTHORISED MAKERS, 



KROHNE & SESEMANN, 



8, DUKE STREET, MANCHESTER SQUARE, LONDON, W. 



FLETCHER'S NEW FURNACE. 



A perfect furnace for all purposes : can be used anywhere, with or withou' 

 gas. Simple, cheap, not liable to damage, and always ready for instant use- 

 Will fuse 6 lbs. metallic nickel to pour clean. The power is under the most 

 delicate control, and delicate enamels can be fused in the open flame without 

 protection. It is perfectly adapted for the most precise chemical operations, 

 small forgings, steel and iron castings, &c., and has been carried about fields 

 for heating nvets for fencing. 

 ^_ _ Illustrated List on Application. 



T. FLETCHER, Museum Street, Warrington. 



W. F. STANLEY, 



Mathematical Instrument Manufacturer 



To H.M/s Government, Council of India, Science and Art 

 Department, Admiralty, &c. 



Mathematical, Drawing, and Surveying Instruments of every description, of 

 the highest quality and finish, at the most moderate prices. 



Price List post free,, > Engine Divider to the Trade, 

 ADDRESS- 

 GREAT TURNSTILE, HOLBORN, LONDON, W.C. 



3. C. TISLEY Sc Co. 



OPTICIANS, '■' 

 172, BROMPTON ROAD, S.W. 



(Close to South Kensington Museum). 



THE PHONEIDOSCOPE 



An Instrument for Observing the Colour-Figures of Liquid Films under the 

 action of Sonorous Vibrations. 



Being a visible demonstration of the Vibratory and Molecular Motion of a 

 Telephone Plate. 

 The PHONEIDOSCOPE, with 3 Discs, Bottle of Solution, Descriptive 

 Pamphlet, &c., in Cardboard Box, \os. 6d, 



MANUFACTURED AND SOLD WHOLESALE AND RETAIL BY 



S. C. TISLEY & CO., 172, BROMPTON ROAD, LONDON, S.W. 



TELEPHONIC ELECTRICITY. All Materials suppUed for experi- 

 mental purposes. 



Price Lists of Electrical and Acoustic A^paratus^ tuith Drawings and 

 Description of tht Harmono^aph, Post Free, zd* 



OLDRIDGE'S BALM OF COLUMBIA 



Prevents Baldness and the Hair turning Grey, and forms the 

 Basis of a Magnificent Head of Hair, Strengthens Weak Hair, 



and causes the 



WHISKERS AND MOUSTACHIOS to GROW FREELY. 



Sold everywhere, 3^. 6d., ds. 6d., and ll^., 



Wholesale and Retail. 



K, WELLINGTON STREET, STRAND, LONDON, W.C. 

 Established Sixty Years. 



MICROSCOPIC OBJECTS. 



Horn Sections, Blood Discs, Feathers, Hairs, Sections of Bone and Teeth, 

 Fish Scales, Anatomical Preparations from the Human Subject and Lower 

 Animals, Palates of MoUusca, Sections of Shells and Pearls, Polyzoa, whole 

 Insects, Pai-asites, parts of Insects, Ossicula, Spines, &c., of Echim-dcr- 

 mata, Spicules of Sponges and Gorgonias, Foraminifera, Botanical Prepara- 

 tions, Diatomacesc, SalU, Crystals, Sections of Rocks, Fossils, Mineral*, 

 &c. 



Ochreoui Iron in Moss-like Forms in Calcite, u- 6</. post-free. 



Stellar Mica, or Canadian Phlogopite, if. -^d, post-free. 



Catalogues free. 



THOS. D. RUSSELL, 

 48, ESSEX STREET, STRAND, LONDON, W.C, 



JOHN NORMAN, 



MANUFACTURER OF 



MICROSCOPES, OBJECTS, CABINETS, 



TABLES, LAMPS, 



And all Glass Appliances for Mieroscofes, 



HAS OPENED NEW AND EXTENSIVE PREMISES AT 



34, Whitecross Street, Cripplegate, E.C. 



Lists post free on application. 



NEW ILLUSTRATED CATALOGUE of ELECTRIC 



SIGNALS, &c., with Instructions for Fixing. 150 Diagrams. Just -ut, 

 post free, 6 Stamps. 



EDWARD PATERSON, 



Electrical Engineer and Scientific Apparatus Manufacturer, 



3, BEDFORD COURT, COVENT GARDEN, LONDON 



STEAM WORKS, GRAY'S INN ROAD. 



Experiments in Electric Lighting carried out. 



Elictricai Af^aratiis of all Descrijithns for Ltcturt Purposes Loaned out. 



APPARATUS for CLASS DEMONSTRATION and for SCIENCE 



SCHOOLS. 

 ELECrRIC LIGHT APPARATUS. 

 SIEMEN'S and GRAMME'S DYNAMO MACHINES and LAMPS 



for Hire and Purchase. 

 LARGE ASSORTMENT of RUHMKORFF COILS and VACUUM 



TUBES. 

 PROFESSOR HUGHES' MICROPHONE. 

 ELECTRIC BELLS and INDICATORS. 

 TELEPHONES and TELEPHONE CALL BELLS, WIRE, &c., for 



Fixing. 

 EDISON's ELECTRIC PEN 1% 8j. 



ELECTRIC and MAGNETIC APPARATUS of all Descriptions. 

 Illustrated Catalogue Electrical Apparatus, Part i. Post free, 6 Stamps. 

 do do Electric Signals, Part 2. Post free, 6 Stamps. 



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. 



IS, FRITH STREET, SOHO, W. 



