In pursuance of Section 33 of the Coal Mines Act, 1911. I hereby approve, until further Order, for use in all mines to which the Act applies the " Oldham " Miner's Electric Safety Lamp described in the Schedule to this Order and subject to the conditions specified in the Schedule.
R. McKenna, One of His Majesty's Principal Secretaries of State. Whitehall,
13th March, 1913.
The " Oldham " Miner's Electric Safety Lamp, the general design of which is shown in the accompanying plate, possesses the following essential parts:-
(1) A solid drawn steel case (tinned).
(2) An electrical accumulator, the terminals of which are fitted with spiral springs carrying rubbing contacts: the construction of the accumulator being such as to prevent escape of the liquid, what ever the position of the lamp, whilst allowing the escape of gas generated by chemical action.
(3) A top screw plug carrying the bulb, protecting glass, pillars and crown, and forming a flame-tight connection with the case: the protecting glass, pillars and crown, being of any of the types shown in the plate.
(4) A bottom screw plug carrying the accumulator and forming a flame-tight connection with the case.
(5) An efficient locking device of one or other of the following types, to prevent unauthorized persons from unscrewing the bottom plug, viz.
(a) A brass locking bolt, held in position by a lead rivet.
(b) A magnetic lock, so constructed that the locking bolt can only be withdrawn by applying the pole of an electromagnet against the cover of the lock.
(6) Provided
(1) That the total weight of the lamp is not more than 5 lbs. 4 ozs.
(2) That the strength of material and attachments throughout the lamp is not less than in the sample submitted to test on the 7th and 8th January, 1913.
(3) That the lamp shall be capable of maintaining a light of not less than 1 candle-power all round in a horizontal plane throughout a period of not- less than 9 hours, and also of giving a light
of not less than 1.5 candle-power over an are of 45 degrees in a horizontal plane.
(4) That the lamp has been made at the works of Messrs. Oldham and Son, at Denton. near Manchester.
(5) That the lamp shall have marked upon it its name and the name of the maker.