CXXXVl 



NATURE 



\August 2 1, 1879 



PURE WATER AND WATER ANALYSIS. 



WANKLYN & COOPER'S 



PATENT MOIST COMBUSTION PROCESS, 



A REGISTERED SET OF 



APPARATUS AND RE-AGENTS. 



The Only Process by which the Total Organic Matter In Potable Water can be Ascertained: 



The Re-agents are Prepared in Professor Wanklyn's Laboratory^ 



and. guaranteed by Mm. 



Price, with Instructions, in a Lined Mahogany Cabinet, £3 3s. 



SOLE AGENTS- 

 JOHN J. GRIFFIN AND SONS, 



MANUFACTURERS OF 



CHEMICAL AND PHILOSOPHICAL INSTRUMENTS. 



22, GARRICK STREET, COVENT GARDEN, W.C. 



PROFESSOR HUGHES' AUDIOMETER. 



The only perfect measurer for testing the hearing power. Vide Dr. Richardson's Report to the Royal Society, 

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



SOLE AUTHORISED MAKERS, 



KROHNE & SESEMANN, 



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



W. L ADD 8c CO. 



SCIENTIFIC INSTRUMENT MANUFACTURERS 



{By appointment to the Royal Institution of Great Britain), 

 II AND 12, BEAK STREET, REGENT STREET, W. 



IMPROVED HOLTZ ELECTRICAL MACHINES, with 4 to 24 Plates. Immediately available in .any condition of the at • 

 LADD'S DYNAMO-MAGNETO MACHINE and GRAMME'S MAGNETO-ELECTRIC MACHINE for Laboratorj' use. 



Physical Apparatus of every Description. 

 ILLUSTRATED CATALOGUE, SIXPENCE. 



TO BOTANISTS, TOURISTS, ARTISTS, SPORTS- 

 MEN, AND TRAVELLERS. 



PORTER'S NEW REGISTERED 



ANTI GNAT AND MOSQUITO VEIL, SPECTACLES, 



AND FACE AND NECK PROTECTOR 



Gives entire protection against the stings of Gnats and all other Flies ; also 



an effectual guard against Dust. 

 Packed in Pocket Travelling Tin Case. Sent free to all parts on receipt of 



Cheque cr P.O. Order for 15s. 



CAEY'S, 



OPTICIAN AND MATHEMATICAL INSTRUMENT 



MAKER TO THE ADMIRALTY, &c., &c., 



181, STRAND, LONDON. 



LIGHTNING CONDUCTORS. 



Experience, accumulated since the time of Benjamin Fraaklin, proves 

 conclusively that a Conductor made of Copper of adequate size is the bi:st 

 of all appliances for the protection of every description of building from the 

 destructive eflects of lightning. 



NEWALL & CO.'S 



PATENT COPPER LIGHTNING CONDUCTOR, 



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

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

 Conductor ever offered to the public. 



It is Simple in its application, no insulators being required, and it costs 

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

 a. S. NEWAIiI. & CO., 130, STRAND, W.C. 



36, WATERLOO ROAD, LIVERPOOL . 

 68, ANDERSTON QUAY, GLASGOW. 

 MANUFACrORY-GATESHE -VD-ON-TYNB, , 



