AMNH LIBRARY 



100164816 



SCIENCE-GOSSIP. 



JOHN J. GRIFFIN & SONS, Ltd., 



Chein'cal, Pliilosopliical, and Photograpljic Instrument Makers, 



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



Physical AND Chemical Apparatus of Every Description. 



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A. Fvw Advantages .- — Compact. Complete in itself. No trouble in working. Gives a eontinuous, uniform 

 light. Gases not generated nnder pressure. Perfectly safe. Its containing box can be .tised as a Lantern 

 table while the apparatus is working inside. Total weight about 30 lbs. 



Ftdl particulars and inspection upon a])plication. 



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



JAMES J. HICKS, 8, 9 & 10, Hafton 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 Avheu reqtiired, and "put out of gear" 

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

 absoluteljr impervious to the influence of variations in atmospheric pres- 

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

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

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

 the Times of December I7th, 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 O'l of an incli. He 

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

 .Aneroid in obscrvntions made for altitude, and in determining differences 

 of level." 



" 11 is licyuiid do\ibt a wonderful instrununii," Sex:. (Presa). 



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 JOs. 

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



London : Pi-intcd hy W. M. HuTf:HiNGS, The Chicli ;ster Press, Chancery Lane, W.C. 



