A WKKKLY ILLUSTRATED JOURNAL OF SCIENCE. 



" To the solid gfoiind 

 Of Nature trusts the mind which builds far aye.'' 



-Wordsworth. 



X-RAY FOCUS TUBES. 



The " Focus" Tubes manufactured by 



NEWTON & CO., 



3 FLEET STREET, LONDON, 



are still unrivalled for brilliancy and definition, and are used by 

 nearly all the leading workers. 



Dr. J. Macintyre, of Glasgow, in Nature, September lo, 

 says that with these Tubes he has obtained "some of the best 

 photographic results in the deeper structures of the body." 



In consequence of the large number of these Tubes which have 

 now been sold, it has been possible to reduce the price to 25s. 

 each. With these Tubes and a 6" Coil and Fluorescent Screen, 

 the beating of the heart and the movements of the diaphragm 

 can be readily seen in an adult. 



Fluorescent Screens, intensely brilliant, 



8" X 5", 35s. ; lo" X 8", 63s. 



LIST OF COILS, TUBES, S CUE ENS, &=[. POST FREE. 



BECK'S MICROSCOPES. 



No. 2SA.— THIS MODEL, with 

 l-in. andi-in. Object Glasses, 

 Two Eyepieces, and packed 

 in Polished Mahogany Case, 



£6 10s. 



No. 25B.— THIS MODEL, with 

 |-in. and J-in. Object Glasses, 

 Two Eyepieces, and packed 

 in Polished Mahogany Case, 



£7 5s. 



Ni 



/r/./ rA.'rnvuLAKs free o„ application to 



R. & J. BECK, Ltd., 68 cornhill, London, e.c. 



THE EYE 



Anatomically represented in a Coloured Sectional Chart, with 

 explanatory text. 



By DR. RENLOW. 



Revised and Edited, with an Introduction on Eyesight, by 

 JOHN BROWNING, F.R.A.S., F.R.M.S., 



President of the British Optical Association, Author of " Our 

 Eyes," &c. 



29B.— The addition of Abbe 

 Condenser to 25R with Iri^ 

 Diaphragm and Focussing 

 and Swinging Adjustments, 



£8 15s. 



This Chart shows, in twenty sectional parts, all the principal 

 parts of the Eye ; the Chart is about 10 inches by 8 inches, and 

 is bound with twenty pages of letterpress and si.x engravings 

 in the text. 



PRICE 2s. 6d. NET. 



Scut, Post Free, for 2s. 6d. , by 



MR. JOHN BROWNING, 



OPHTHALMIC OPTICIAN, 



63 STRAND, J.ON DON, W.C^ 



STTivtivi Eie, uor .TP.A.'ys. 



NEGRETTI & ZAMBRA'S 



BINOCULARS AND TELESCOPES. 



Makers of the " OFFICER OF THE WATCH" TELESCOPE, 

 in use on all the vessels of H.M. Navy. 



Nickel-plated, covered 

 Leather. 

 PRICE £2 10s. 



Perfect Definition &IH1 



"ARMY SIGNALLING" TELE.SCOPE. 



£2 2s. 



£2 2s. 



As supplied by NEGRETTI & ZAMBRA to the War Office. 



Length, when closed, ir inches. Combining high power and portability. 



NEGRETTI & ZAMBRA, 



SOIBNTIPIO INSTRUMENT MAKERS to the QUEEN 



38 HOLBORN VIADUCT, E.C. 



Branches : 45 CORNHILL; 122 REGENT STREET. 



PKJtt Ll; 



