A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE. 
“*To the solid ground 
O, Nature trusts the mind which builds for aye.”-—WorvDsSWoRTH. 
No. 1416, VOL. 55] 
THURSDAY, DECEMBER 17, 1806. 
[PRICE SIXPENCE. 
Registered as a Newspaper at the General Post Office.] 
{All Rights are Reserved. 
INDUCTION COILs. 
APPS’ PATENTED INDUCTION COILS are now manufactured 
concurrently by 
NEWTON & CO., 3 FLEET STREET, LONDON. 
“xX” RAY “FOCUS” TUBES, 25s. - 
FLUORESCENT SCREENS, 35s. and 68s. 
Complete Apparatus for Réntgen “‘X” Rays, with 
Coils and Fluorescent Screens, &c. 
Detailed List on Application. 
BECK’S MICROSCOPES. 
No. 25A._THIS MODEL, with 
I-in. and 4-in, Object Glasses, 
Two Eyepieces, and packed 
in Polished Mahogany Case, 
£6 10s. 
258.—THIS MODEL, with 
No. 
3-in. and } 
Two Eyepieces, and packed 
in Polished Mahogany Case, 
£7 5s. 
298.—The addition of Abbe 
Condenser to 25B with Iris 
Diaphragm and Focussing 
and Swinging Adjustments, 
£8 15s. 
No. 
STAND No. 25. 
FULL PARTICULARS FREE on APPLICATION to 
R. & J, BECK, LTD., 68 CORNHILL, LONDON, B.C. 
-in. Object Glasses, | 
BROWNINGS SPECTROSCOPES. 
THE MINIATURE SPECTROSCOPE. 
This instrument will show many of Fraunhofer’s lines, the 
bright lines of the metals and gases, and the absorption bands in 
coloured gases, crystals, or liquids. 
| Price, with Plain Slit, £1 25. ; 
| Morocco Case, £1 145. ; ditto, 
in Morocco Case, £2 6s. 
Iilustrated Catalogue of DA Post Free. 
JOHN BROW 'N-T-N'G; 
MANUFACTURING OPTICIAN, 
63 STRAND, LONDON, WC. 
CHRISTMAS 
PRESENTS. 
ditto, with Adjustable Slit in 
with Achromatic Lens, &c., 
THE 
CINEMATOGRAPH. 
This Apparatus is capable of producing Animated Pictures of the highest 
and can be easily manipulated ‘without the assistance of a skilled 
operator by following the instructions supplied w ith same. 
Price, including Lantern, Oxyhy drogen Burner Limes, &c., complete, £36. 
Films for same, £4 10s. each. 
NEGRETTI & ZAMBRA, 
38 HOLBORN VIADUCT, E.C. 
Branches—45 CORNHILL, and 122 REGENT STREET. 
class, 
