A WEEKLY 
[LEUSDRATED JOURNAL OF SCIENCE. 
‘To the solid gr 
Of Nature trusts the mind which builds for aye.” 
ound 
—WORDSWORTH. 
No. 1424, VOL. 55] THURSDAY, FEBRUARY 11, 1897. [PRICE SIXPENCE. 
Registered as a Newspaper at the General Post Office.] [All Rights are Reserved. 
NEWTONIAN X-RAY CURRENT METER. 
The principal difficulty in 
X - Ray 
exposure. This can easily be 
done by using an X-Ray 
Current Meter. The arrange- 
ment answers the purpose 
admirably. The same con- 
ditions can, if desired, be re- 
produced from day to day, 
and the voltage being con- 
IEWTON & C2 
LONDON 
Aurcaee 
on which the rapidity of ex- 
can be varied as desired and 
adjusted to the greatest 
nicety by the tension screw 
of the coil. 
““X” Ray Current Meter, comprising Ammeter and Volt- 
meter suitable for use with Induction Coils, £5 5s. 
SOLE Makers: 
NEWTON & CO. 
3 FLEET STREET, LONDON. 
List of Apps-Newton Induction Coils and X-Ray Apparatus Post Free 
on application. 
BECK’S MICROSCOPES. 
5a.—THIS MODEL, with | 
I-in. and }-in. Object Glasses, 
Two Eyepieces, and packed 
in Polished Mahogany Case, 
£6 10s. 
. 258. THIS MODEL, with 
§-in, and }-in. Object Glasses, 
Two Eyepieces, and packed 
in Polished Mahogany Case, 
£7 5s. 
. 298.—The addition of Abbe 
No 
Condenser to 258 with Iris 
i vail Diaphragm and _ Focussing 
_ = and Swinging Adjustments, 
STAND No. 25. £8 15s. 
FULL PARTICULARS FREE on APPLICATION to 
R. & J. BECK, LTD., 68 CORNHILL, LONDON, E.C. 
photography has | 
been to judge the length of 
stant, the number of amperes, 
posure then entirely depends, | 
ASTRONOMICAL “TELESCOPE. 
With 3-inch Achromatic Object-Glass of excellent quality, with brass body, 
one Terrestrial and two Celestial Eyepieces, in Case complete. Guaranteed 
to be capable of dividing Double Stars and showing Saturn's Ring and 
Jupiter's Belts. 
Price £6 10s. Od. 
Catalogue of Astronomical Telescopes sent Free. 
_JOHN BROWNING, 63 STRAND, LONDON, W.C. 
“NEGRETT! & ZAMBRA’S THERMOMETERS. 
The outside Window Bracket Thermometer 
enables the observer to read the Present 
Temperature from inside the House. 
PRICE 2l/- and upwards, 
Accurate Thermometers for all Purposes. 
ILLUSTRATED PRICE LISTS FREE TO ALL PARTS OF THE WORLD. 
NEGRETTI & ZAMBRA, 
Scientific Instrument Makers to Her Majesty the 
Queen and British and Foreign Governments, 
38 HOLBORN VIADUCT. 
BRANCHES— 
45 Cornhill, and 122 Regent Street, London. 
Photographic Studios : Crystal Palace. 
