Registered as a Newspaper at the General Post Office.] 
A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE: 
“To the solid ground 
Of Nature, trusts the mind which builds for aye."—-WoRDswoRTH. 
No. 2464, VoL. 98] 
X-RAY TUBES 
Of ‘all descriptions Made, 
Repaired, & Re-exhausted 
on the Premises. ' 
Coolidge Tubes kept in iden: 
‘NEWTON & WRIGHT, Ltd. 
72-WIGMORE STREET, W. 
Sole Agents for Macalaster Wiggin X-Ray Tubes, 
Undoubtedly the Finest Tubes 
in the World for all purposes, 
DUROGLASS L™: 
14 GROSS STREET, HATTON GARDEN, E.C. 
Manufacturers of 
Borosilicate Resistance Glassware. 
Beakers. Flasks, Etc. 
Soft Soda Tubing for Lamp Work. 
General Chemical and 
Scientific Glassware. 
Special Glass Apparatus Made to Order. 
DUROGLASS WORKS, WALTHAMSTOW. 
AGENTS: 
BAIRD & TATLOCK (LONDON) LTD. 
14 GROSS ST., HATTON GARDEN, E.c. 
THURSDAY, JANUARY 18, 1917 
* [Price SIXPENCE. 
[All Rights Reserved. _ 
| REYNOLDS & BRANSON, Ltd. 
Chemical Glassware, Chemical and Physical Pera 
Makers to His Majesty's Government (Home and Overseas 
* Dominions), Laboratory Outfitters, &c. 
Gold Medals es ee and London. Grand Prix and Gold Medal 
the International Exhibition, Turin. 
STeoue z RENDELL SCIENCE LANTERN. 
The ‘‘ University” Lan 
tern, with Russan_ iron 
hody, sliding baseboard, two 
superior objectives, with rack 
and pinion for focassing, con- 
densers 4} in. diam., plane 
sulvered mirror ‘* A,” which is 
moved by a knoh causing thé 
rays to be reflected upwards 
for the projection of objects 
in a horizontal, plane, silvered 
prism which can be used at 
*C,”orvas an erecting prism 
in mount “D,” limelight 
burner, slide casrier. Price 
opplets: in praygiioe case, 
without reversible adjustable stage’. es : . £11; .8°6 
Ditto, ditto, with “ Pheenix” arc lamp oe = 12.18, 6 
Reversible adjustable stage “‘B" for supporting Ss apel oat 
CXITA,, «0 5 6 
CATALOGUES (Post free). 
Optical Lanterns and Accessory Apparatus. 
Chemical Apparatus and Chemicals, 44 pages. 
14 COMMERCIAL STREET, LEEDS. 
A New Barograph— THE “JORDAN.” ? 
(Regd. Desicn €2871.) 
Shows at a glance the movements of the barometer during 
the preceding days. 
Descriptive Leaflet post free on application to 
NEGRETTI & ZAMBRA, 
38 HOLBORN VIADUCT, E.C.; 
45 CORNBILL, E.C.; 122 REGENT ST., W 
