AMNH LIBRARY 



Till 



100164817 



SCIENCE-GOSSIP. 



JOHN J. GRIFFIN & SONS LD., 



Chemical, Philosophical, and Photographic Instrument Makers, 



MAKERS TO THE ADMIRALTY, WAR DEPARTMENT, INDIA Sr COLONIAL GOVERNMENTS. 



A NEW DOUBLE SURFACE CONDENSER 



(Gribb's Patent.) 



SMALL SIZE. 



SMALL WEIGHT. 



Efficiency equal to a _3 — 



LIEBIG CONDENSER _- 



5 



Times its Size- 



Invaluable in 



a Laboratory. 



—OCr&—— ■■ 



pB^ Full description and particulars 

 upon application. 



General View of Apparat us, 



Section of Condenser. 



20-26, SARDINIA STREET, LINCOLN'S INN FIELDS, LONDON, W.C. 



JAMES J. HICKS, 8, 9 & 10, Hatton Garden, LONDON, 



SCIENTIFIC INSTRUMENT MAKER TO THE WAR OFFICE, 

 INDIA OFFICE, ADMIRALTY, &c, 



Is Sole Maker of the New Patent 



"WATKIN" MOUNTAIN ANEROID BAROMETER. 



The Barometer that all the World has been waiting for, and the only 

 Aneroid that can be put in action when required, and "put out of gear" 

 when it is not wanted for use, and which, when thrown out of action, is 

 absolutely impervious to the influence of variations in atmospheric pres- 

 sure. Travellers and Surveyors will now be able to ascertain correct alti- 

 tudes owing to the marvellous accuracy of this Instrument, which is 

 described at length by Mr. Whymper, the distinguished Alpine climber, in 

 the Times of December 17th, 1898. In 65 readings taken between 1,227 

 and 10,289 feet above the sea, the mean error ascertained by comparison 

 with the Mercurial Barometer was never so much as 01 of an inch. He 

 says : " Extraordinary results may be obtained from Watkin's Mountain 

 Aneroid in observations made for altitude, and in determining differences 

 of level." 



" It is beyond doubt a wonderful instrument," &c. (Press). 



It is made in Aluminium for lightness, in either 3 in. or 4| in. sizes, with Sling Leather Case 

 and supplied at the following prices :— Scale to 5,000 ft., £5 5s. To 10,000 ft. £5 lOs. 

 To 15,000ft, £5 I5s. To 20,000ft., £6. 



London : Printed by W. M. Hutohings, The Chichester Press, Chancery Lane, W.C. 



