A WEEKLY 
ILLUSERALED: JOURNAE FOP TSCHENGE. 
“To the solid ground 
Of Nature trusts the mind 7% 
which builds 
—WOoRDSWORTH. 
oa = oF 
jor aye. 
No. 1419, VOL. 55] 
THURSDAY, JANUARY 
7, 1897. [PRICE SIXPENCE. 
Registered as a Newspaper at the General Post Office.] 
[All Rights are Reserved. 
PEW Tune X-RAY CURRENT METER. | 
The principal difficulty in 
X-Ray photography has 
been to judge the length of 
This can easily be 
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- 
stant, the number of amperes, 
on which the rapidity of ex- 
posure then entirely depends, 
can be varied as desired and 
adjusted to the greatest 
nicety by the tension screw 
: of the coil. 
“x” Rav Current Meter, comprising Ammeter and Volt- 
meter suitable for use with Induction Coils, £5 5s. 
Sore MAKERS: 
NEWwWTron s& CO. 
3 PRM teSEREET, LONDON. 
List of Apps-Newton Induction Corts and Apparatus Post Free 
on applicati 
e xposure. 
done by 
HEWTON SCP 
Longon 
A\-Ray 
NALDER BROS. & CO. 
LONDON. 
_ N. CG. S. 
THOMSON 
REFLECTING 
GALVANOMETER. 
&000 OHMS RESISTANCE. 
VERY SENSITIVE. 
PRICE 
£939 10 O 
Write for CATALOGUES. 
Cable Address: 
SECOHM, LONDON. 
No Agents in U.S.A. 
This instrument delivered Free anywhere in U.S.A. 
for 60 C.0.D. 
X-RAY COMPLETE SETS. 
Ser A. Including 3-inch Coil, our own make Batteries, Focus 
Tube, Tube Holder, Barium-Platino-Cy anide Screen, 
7 in. X 5 in. £13 0 0 
Ser B. Including Ganch Goil: Batteries, Lars rer ; Focus Tube, 
Tube Holder, Barium- Platino- Cyanide Screen, of in. x 7in. £23 10 0 
BARIUM-PLATINO-CYANIDE SCREENS. 
EXCELLENT FLUORESCENCE, in neat Frames with Handles. 
7 in. X 5 in., 21S.; of in. X 7 in., 325- 6d. 3 11} in. X gf in., 555. 
JOHN J. GRIFFIN & SONS, 
22 GARRICK STREET, LONDON, W.C. 
- Naan & ZAMBRA’S THERMOMETERS. 
The outside Window Bracket Thermometer 
enables the observer to read the Present 
Temperature from inside the House. 
PRICE 2l/- and upwards. 
Accurigté 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. 
Crystal Palace. 
Photographic Studios : 
