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/ r^s r^ ^ 



A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE. 



" To the solid ground 

 0/ Nature trusts the mind which builds for aye.'' — Wordsworth. 



IWE-WTOIW <SC 00., 



CIKNTIFIC INSTRUMENT 



MAKERS 



TO HER MAJESTY THE 



QUEEN 



AND THE GOVERNMENT. 



Phi 



ENT Makers 

 Appointmen- 



OYAL ■ InSTI'I 



Great Br 



Makers of every descrip- 

 tion of OPTICAt. and 

 PHYSICAL APPARA- 

 TUS of the highest class, 

 for Colleges, 



Catalogue of 

 OPTICAL LANTERNS, 

 PROJECTION APPARA- 

 TUS, and SLIDES, M. 

 WIMSHURST ELECTRICAL MACHINES. 



Best Quality, 12 in., 70J. : 15 in-, £,S '°^- < >8 '"•• i>^ '°^- Multiple-Plate 

 Machines, ^£20 to £iw. As made for the Science and Art Depart- 

 ment and the Universities of 0.\ford, Cambridge, London, Sydney, 

 N.S.W., McGill, Montreal, &c. 



3 FLEET STREET, TEMP LE BAR, LONDON, E.G. 

 GRIFFIN'S NEW FORM OF APPARATUS 



For the ABSOLUTE 



EXPANSION OF SOLIDS 



(Weedon's Patent). 



A H ISTORY OF 

 ASTRONOMY. 



By ARTHUR BERRY, 



Fellow of King's College, Cambridge. 

 With very numerous Illustrations. Crown Svo, 6.r. 



"Conveys a vast amount of information." — Lilaattire. 

 " Supplies in a very satisfactory way a decided desideratum." — 

 Alheihtum. "A work which will be of the greatest value to 

 all serious students of astronomy." — .Manchester Guardian. 



JOHN MURRAY, Albemarle Street, W. 



NEGRETTI & ZAMBRA'S 



MPROVED 



One great merit in the dcsig>i of tlii- -Xi'i'.n.itn-. i-, (h.it u i^ 

 TJ/trMrt^m-rt/ method, and does not depernl .nail Lipon njaiLai uu. 

 magnification that so frequently are a dilliculty in early I'ractical Pliysics 

 work. The measurement reduces itself to the readings of two Micrometer 

 Scretvs. 



A DIRECT MECHANICAL METHOD. 



ABSOLUTE READINGS OBTAINED. 

 SIMPLEST DESIGN. 



Wrili for Particulars and Specimen Curves obtained. 

 SOLE MAKERS : 



JOHN J. GRIFFIN & SONS, l^ 



20-26 SARDINIA STREET, LONDON, 'W.C. 



SELF-RECORDING 



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PRICE LIST 



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IN'VKNTKli AND .MADE ONI.V KV 



NEGRETTI & ZAMBRA, 



Scientific Instrument Makers to Her Majesty the Queen, 

 38 HOLBORN VIADUCT, E.G. 



Branches— 45 Cokniull, E.C. , and 122 Regent Street, W. 



