A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE. 



X-RAY "FOCUS" TUBES. 



The " Focus" Tubes made hy Xewtox & Co., in accordance 

 with the experiments conducted in the Chemical Laboratory at 

 King's College, are still unequalled for rapidity and definition. 



Price 35s. each. 



The above are suitable for Coils givinj; 2 ' .'ipark and over. 



Special "Focus" Tubes, 42s. each. 



The above are suitable for Coils giving from 7" to 10" sparks. 



" The definition given by your focus tubes is excellent." — Prof. Oliver 

 J. LoDGK, University Coitege, Liverpool. 



"Your focusing tube ha.s worked very well, and as soon as you have 

 another similar one that you can spare me I shall be glad to have it." — 

 Prof. A. Schuster, The Oivens College, Manchester, 



" We have got excellent results with the focus tubes."— Prof. W. 

 Heatdn, University College^ Nottingham. 



*' The focus tube you sent gives remarkably sharp shadows." — Prof. A. 

 S. Butler, The Unr.'ersity, St. Andrews, N.B. 



" I have tried a very large number of vacuum tubes sold by different 

 makers for the purpose of giving the X-rays, and find your ' focus tubes ' to 

 be far and away superior to anything as yet in the market." — Prof. W. F. 

 Barrett, Royal College of Science, Dublin. 



" Les risult.lts sunt merveilleux."— Dr. Henri van Heirck, Jantin 

 Botanique d 'A nvers. 



Sole M.^kers : 



3 FLEET STREET, LONDON. 

 Helium and Argon Spectrum Tubes Now Ready, \os. 6d. each. 



BROWNING'S SPECTROSCOPES. 



The Student'; 

 superior workn 



xtremeiy dense glass, of very 



Spectroscope ha; 

 anship ; the circl 



the sht is furnished with a reflecting prism, by mean; 

 which two spectra can be shown in the field of view at the same time, 

 instrument will divide the D line in the Solar Spectrum, or the yellow Sodi 

 lines distinctly. With a slight alteration of the adjustments, the ' 

 can be used for taking the refractive and dispersive powers of solids or 

 liquids. The Student's Spectroscope is the best instrument for the Labora- 

 tory and for all general work in Spectrum Analysis. 



PRICE, COMPLETE IN CABINET, £6 lOs. Od. 



lilusfraten Catnlogue of SpeUroscopcs, post free. 



of 



The Frena Camera 



****************** 



K-eoHAIjHl up-Jo-li;\Ti 



PARTICULARS of this 



unique HAND-CAMERA 



may lie had FREE on 



application to 



R. & J. BECK, 



I, III., 



68 CORNHILL, 



LONDON, E.G. 



JOHN BROWNING, 63 STRAND, LONDON, W.C 



NEGRETTI & ZAMBRA, 



SOLE MAKERS OF 



JORDAN'S (PATENT) SUNSHINE RECORDER. 



New Simplified Model, 

 adjustable for any 

 latitude, and tho- 

 roughly efficient. 

 Price £1 7s. 6d. 



Sensitised Charts, 

 5s. per 100. 



NEGRETTI 



ZAMBRA, 



ILLUSTRATED DESCRIPTION POST FREE. 



Telephone No. 6583. Telegraphic .\ddress, " Negretli, Londo 



