Ph Coe 
A WEEKLY ILLUSTRATED JOURNAL ‘OF: SCIENCE. 
“To the solid ground 
Of Nature trusts the mind which builds for aye."—Worpswortn. 
__No..2460, VoL. 98) 
THURSDAY, DECEMBER -21, 1916. 
-. [Prick SIXPENCE. 
~ [Al Rights Reserved. 
Registered as a Newspaper at the General Post Office.] 
X-RAY TUBES 
Of all descriptions Made, 
Repaired, & Re-exhausted 
on the Premises. 
Coolidge Tubes kept in stock. 
NEWTON & WRIGHT, Ltd. 
72 WIGMORE STREET, W. 
“Sole Agents for Macalaster Wiggin X-Ray Tubes, 
Undoubtediy 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. 
DUROCLASS WORKS, WALTHAMSTOW. 
AGENTS: 
BAIRD & TATLOCK (LONDON) LTD. 
14 CROSS ST., HATTON GARDEN, E.Cc. 
REYNOLDS & BRANSON; Lta., 
MANUFACTURERS of CHEMICAL and PHYSICAL APPARATUS. 
Awards: Gold Medal, Allahabad, London and Turin. 
5 Grand Prix, Turin. 
GOODMAN’S PATENT PLANIMETER. 
Ii 
Mig Mat : fil Hil 
Planimeter (Goodman’s), for measuring areas, with instructions, giving 
a direct reading, and suitable for all Technical schools and workshop 
purposes, in leather case . £0 16 6 
GOODMAN’S PATENT AVERAGING INSTRUMENT. 
Averaging Instrument (Goodman’s), for Indicator Cards, in leather 
a «- £0 4 
case = ty rr = oo ast 6 6 
Descriptive Circular post free on application. 
1a COMMERCIAL STREET, LEEDS 
A New Barograph—THE “ JORDAN.” 
(Regd. Design 62871.) 
Shows at a glance the movements ot the barometer durin 
the preceding days. j 
Descriptive Leaflet post free on application to 
NEGRETTI & ZAMBRA, 
38 HOLBORN VIADUCT, E.C.; 
' 45 CORNHILL, E.C.; 122 REGENT ST., W. 
