1206

[ SUPPLEMENT PAGE II. ]

THE COLLIERY GUARDIAN.

December 6, 1918.

SIMPLE! CIRCULATOR

FOR EFFICIENCY AND ECONOMY

For further particulars apply to

THE

LONDON SIMPLE! ENGINEERING C° L

LANCASHIRE BOILER FITTED WITH CIRCULATOR.

1O%to15%MORE STEAM
r5’/oTO8%SAVINGn.FUEI<

Bolton House, Gullum Street, Fenchurch Street, E.C- 3

Telephone—AVENUE 872.

LABORATORY 20, CULLUM STREET, EC. 3.

Telephone—CENTRAL 11029.
Telegrams—“ LONPLET, FEN, LONDON.”

SURVEYING INSTRUMENTS

HOW DO YOU COMPLY WITH
REGULATION No. 124 of the O
COAL MINES ACT of 1911 ■



The test is rendered prac-
ticable and easy by means
of this Induction Regulator,
specially designed for ser-
vice in COAL MINES.



Davis’s

Cranked

Dial.

Theodolites,
Levels,
Barometers,
etc.

DAVIS’S IMPROVED HEDLEY DIAL WITH CRANKED LIMB,
ENABLING SIGHTS TO BE TAKEN TO ANY DEGREE FROM
LEVEL TO 90 DEGS. UP OR DOWN.

Davis’s Surveying Instruments
are used in the majority of Mines in the
United Kingdom, the Colonies, and other
parts of the World.

Write for Catalogue Section 27.

SWITCHGEAR & COWANS LTD>

SPRINGFIELD LANE, SALFORD, MANCHESTER.

PLOTTING INSTRUMENTS

for Railways, Mining Engineering, and Field work.

SEND FOR 'LIST No. 411 A.

JOHN DAVIS & SON

(Derby) LTD

ALL SAINTS WORKS, DERBY;

& 17, Victoria St., Westminster, London, S.W.

Telegrams—“ David, Derby.” Telephone—240 Derby.