July lo, 1879] 



NATURE 



Ixxxvii 



BARCLAY & SON, 



138, REGENT STREET, LONDON. 

 To Her Majesty and H.R.H. the Prince of Wales. 



DUPLEX LAMPS. 

 MODERATOR LAMPS. 



READING LAMPS. 



MICROSCOPE LAMPS. 



BEST COLZA OIL. 



A I KEROSINE OIL. 



WAX, SPERM, 



AND 



PARAFFINE CANDLES. 



ILLUSTRATED CATALOGUES POST FREE. 



NEW ILLUSTRATED CATALOGUE of ELECTRIC 



SIGNALS, &c., with Instructicns for Fixing. 150 Diagrams. Justout, 

 post free, 6 Stamps. 



EDNA/ARD 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. 



Electrical A/'/^arat Its p/ all Dcscriptlotis for Lecture Purposes Loaned out, 



APPARATUS for CLASS DEMONSTRATION and for SCIENCE 



SCHO. )LS. 

 ELECrRIC LIGHT APPARATUS. 

 SIEME-V'S and GRAMME'S DYNAMO MACHINES and LAMPS 



for Hire and Purchase. 

 LARGE ASSORTMENT of RUHMKORFF COILS and VACUUM 



TUBES. 



i PROFESSOR HUGHES' MICROPHONE. 

 ! ELECTRIC BELLS and INDICATORS. 

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



EDISOn'^S ELECTRIC PEN IZ 8j. 



ELECTRIC and MAGNETIC APPARATUS of all Descriptions. 

 Illustrated Catalogue Electric.1l Apparatus, Part i. Post free, 6 Stamps, 

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



C. TISLEY & Co 



OPTIC I ANS, ' 



172, 



BROMPTON ROAD, S.W. 



(Close lo South Kensington Museum). 



THE PHONEIDOSCOPE 



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

 action of Sonorous Vibrations. 



Beine 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, lor. dd. 



MANUFACTUIIED AND SOLD WHOLESALB AND UTAIL BY 



S. C. TISLEY & CO., 173, BROMPTON ROAD, LONDON, S.W. 

 TELEPHONIC ELECTRICITY. All Materials supplied for experj- 



menul purposes. 

 Price Lists of Electrical and Acoustic Affaratus, with Drawints and 

 Description of the Harmono^afh, Post Free, id. 



The LANCASTER POCKET CAMERA 



for plates 4J X 3J inch, having three double dry-plate Slides. Umbrella 

 Stand, best Lens with plate of Diaphragms, &c., &c., jCs. i'articulars 

 free. 



The LANCASTER CARTE PHOTOGRA- 

 PHIC APPARATUS, with Chemicals, &c., &c., complete, f,-^ 51, 

 FIRST QUALITY ASTRONOMICAL TELESCOPES with Object 

 Lenses, by Wray, aj-inch, £s as. ; 2j-inch, £7 los. ; sj-inch, ijio ; 

 3-inch, .£12 loj. ; 3j-inch, ;£i5i5r. ; 4-inch, ^25; 4]-inch, ^£40; 

 5-inch, £s5, &c. Capital Student's Microscope, £^ 3s. Collegian's 

 First Quality Microscope, jC^ 5s. Illustrated Catalogue, 3 Stamps. 

 J. LANCASTER & SON, Opticians Birmingham. 



W. L A D D & CO., 



Scientific Instrament Manufactnrers 



(By A0ctntm4nt to tki Royal Institution of Great Brttain.)^ 



II & 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, &c. 



LADD'S IMPROVED SELF CHARGING HOLTZ 

 ELECTRICAL MACHINE, with 4 to 12 Plates, in- 

 dexed in a Mahogany and Glass Case. This instrument is 

 immediately available in any condition of the atmosphere. 

 Philosophical Apparatus of every Description. 



Illustrated Catalogue, Sixpence, 



LIGHTNING CONDUCTORS. 



Experience, accumulated since the time of Benjamin Franklin, proTC* 

 conclusively that a Conductor made of Copper of adequate size is the b*sl 

 of all appliances for the protection of every description o£ buildinc from tkre 

 destructive effects of lightiunf. 



NEWALL «& CO.'S 



PATENT COPPER LIGHTNING CONDUCTOR. 



As applied to all kinds of Buildings and Shipping in all parts of the wcr d 

 with unvarying success, is the most Reliable, most Effective, and Cheapest 

 Conductor ever offered to the public 



It is simple in its application, no insulators being required, and it costf 

 only one shilling per foot for the standard siie, which is safe in any storm. 

 R. 8. NEW^ALXi & CO.. 130, STRAND, W.C. 



36, WATERLOO ROAD, LIVERPOOl. 

 68. ANDERSTON QUAY, GLASGOW, 

 MANUFACTORY— CATBSHB ^D-ON-TYNB 



Xow ready, a Revised Edition. 



NEGRETTI & ZAMBRA'S 



ENCYCLOPEDIC 



Illiistratecl and Descriptive 

 CATALOGUE OF 



SCIENTIFIC INSTRUMENTS. 



(Containing very numerous Comparative Tables of Reference and 



Illustrated by upward, of TWELVE HUNDRED ENGRAVINGS, 



Six Hundred Pages, Royal 8vo, cloth, gilt lettered. Price is. 6ti.) 



Optical, Mathematical, Philosophical, Photographic, 



AND 



STANDARD METEOROLOGICAL 

 INSTRUMENTS. 



MANUFACTURED AND SOLD BY 



NEGRETTI AND ZAMBRA, 



opticians and Scientific Instrument Makers to 



The Royal Observatory, Greenwich; IheAdmiralty; Hon. Board of Ordnance; 



Board of Trade; the British Meteorological Society ; the Observatones 



Kew, Toronto, Washington, Victoria ; East Indian Government. 



HOLBORN VIADUCT, E.G. 



ALSO AT 



45, CORNHILL, E.G., it 122, REGENT STREET, W., 

 LONDON. 



