(i) The relighter is so designed that it can be operated only by means of a detachable key of special design.

(ii) The relighter device is stamped with the registered trade mark of the Premier Lamp and Engineering Company, Limited.

(iii) The relighter bars for use in the relighter are supplied by the aforesaid company in a sealed box which is clearly marked with the words "Phoenix Relighter bar, for use in the Premier' No. 7R Lamp. Supplied by the Premier Lamp and Engineering Company, Limited, Leeds, with the approval of the Board of Trade." "Premier" No. 7A.R. Lamp.

This lamp is identical with the "Premier No. 7R Lamp,(a) and the same specification shall apply, subject to the following modifications:

Paragraph (1)—Bonnet or Shield. After the word steel "'insert or aluminium."

Paragraph (2)-Middle Ring. After the word "brass " insert "or aluminium.'

Bottom Ring.-After the word "brass" insert

"or aluminium," and at end of paragraph add:

The bottom ring may be fitted with a ring to shut off the air feed there.

Paragraph (3)—Gauzes-at end of paragraph add:

The gauzes are made of copper in the case of lamps used for surveying purposes.

(2) WOLF SAFETY LAMP COMPANY (WM. MAURICE) LIMITED, STAR WORKS, SOUTH STREET, PARK, SHEFFIELD.

"Wolf-Patterson" No. 7R. Lamp.

The "Wolf-Patterson" No. 7R. Lamp, the general design of which is shown in Plate 3, is a double gauze, spirit flame lamp, with an internal relighter, with air feed through vertical holes and horizontal slots in the middle ring and through slots situated below the glass, protected by double gauzes. It consists of the following essential parts:(1) Bonnet or Shield of stamped steel, with or without reinforced upper part, and with a securely fastened steel crown: furnished with outlet holes immediately below the crown, provided that the bottoms of the holes are not less than -inch above the top of the outer gauze. (2) Middle Ring, of brass, riveted to bonnet, provided with vertical air-inlet holes of total area not exceeding 0.3 square inch and with horizontal air-inlet slots of total area not exceeding 0.4 square inch. (3) Pillars, of brass; five, so arranged that a straight line touching the exterior parts of adjacent pillars does not touch the glass.

(4) Bottom Ring, of brass, with a flanged ring forming a baffle against a horizontal current entering the air admission slots. The bottom ring may be fitted with a ring to shut off the air feed there.

(5) Gauzes or not less than 28 S.W.G. steel wire, 784 meshes to the square inch, with double folded lap seams formed to fit flanges of the inner and outer base rings, and so secured to the same by punch indentations or rivets as to make strong and flame-tight joints. The arrangement of the gauzes in the lamp is such that they form the seating necessary to hold the glass firmly in position, thus preventing the possibility of the lamp being put together without them.

(6) Glass, of an approved brand, cylindrical in form, and within the dimension limits and bearing one of the size marks specified below: furnished with top and bottom asbestos washers to ensure flame-tight joints with the gauzes and retaining ring.

(a) See page 281 and Plate 2 of this Order.

THE WOLF SAFETY LAMP COMPANY (WM. MAURICE),

(7) Glass Retaining and Air Admission Ring.-The lamp is fitted with a combined glass retaining and air admission ring with 6 slots of total area not exceeding 0.6 square inch, protected by double securely fastened brass gauzes of not less than 28 S.W.G. 784 meshes to the square inch. (8) Spirit Vessel of stamped steel, with a securely fastened brass screwed ring to fit the bottom ring, with slots cut in the threads to engage the pawl of the magnetic lock; of capacity sufficient to provide the required light for the required time as specified in paragraph (ii) below; fitted with a flat Hth inch burner; and with a thumbscrew wick adjuster so fitted as not to cause the lamp to be dangerous in an explosive atmosphere; fitted with a permanent washer of fibre, leather or other soft but tough material cemented or otherwise securely attached to the recess on the spirit vessel.

(9) Relighting Device. The lamp is fitted with an internal relighter of the pyrophor type, as shown in Plate 3, for use in pursuance of the Safety Lamps (Relighting) Order of 9th December, 1927.(a)

(i) The relighter is so designed that it can be operated only by means of a detachable key of special design.

(ii) The relighter device is stamped with the registered trade mark of the Wolf Safety Lamp Company (Wm. Maurice) Limited.

(iii) The relighter bars for use in the relighter are supplied by the aforesaid Company in a package which is clearly marked with the words "Pyrearthium' Relighter Bar, for use in the "WolfPatterson" No. 7R. Lamp, supplied by the Wolf Safety Lamp Company (Wm. Maurice) Limited, Sheffield, with the approval of the Board of Trade."

(10) Locking Device.-One or other of the following:

(a) A magnetic lock so constructed that the pawl which engages with slots in the spirit vessel can be withdrawn only by a powerful magnet.

(b) A lead-rivet lock with a lug cast on the bottom ring, and a second lug securely soldered to the spirit vessel.

(c) A lead-rivet lock with a loose lug riveted around one of the lamp pillars, and the second lug securely soldered to the spirit vessel.

Approval is subject to the further conditions:

(i) That the strength of material and attachments throughout the lamp is not less than in the samples submitted for Official test on the 9th December, 1927.

(ii) That the spirit and the wick used in the lamp shall be such that the lamp shall be capable of maintaining a light of not less than 0.30 candle-power as determined by a pentane standard, all round in a horizontal plane throughout a period of not less than 10 hours.

(iii) That the lamp has been made at the Star Works of the Wolf Safety Lamp Company (Wm. Maurice) Limited, South Street, Park, Sheffield.

(iv) That the lamp shall have marked upon it its name and the
name of the maker.

Part III-Electric Safety Lamps approved for General Use.
(1) BATTERIES LIMITED, HUNT END WORKS, REDDITCH.

This lamp, the general design of which is shown in Plate 4 comprises the following essential parts:

(1) Cylindrical metal case of pressed and welded steel, engaging with the cover or lantern by means of a bayonet joint, below which is a cheese ring making the connection flame-tight.

(a) S.R. & O. 1927 (No. 1156) p. 143.

(2) Cover or lantern on which are mounted the lamp-holder and lamp bulb, with a strong dome-shaped protecting glass, and a contact plate of non-inflammable insulating material with inlaid steel segments. The contact plate is mounted on springs to ensure good electrical conneotion between the segments and the terminals of the accumulator.

Provided with four steel pillars and a crown or hood to which is attached the loop or carrying handle.

(3) 2.5 volt alkaline accumulator, rectangular in shape with welded steel containers. Its capacity is not less than 9 ampere hours with a voltage drop to not less than 2.0. Provided with solid steel terminals. (4) Bulb of the small Edison screw type, having a current consumption of 0-85 ampere.

(5) Magnetic lock securely riveted to the cover. The light may be switched on and off after the lamp is locked by revolving the case whilst holding the lantern.

Approval is subject to the further conditions:

(i) That the total weight of the lamp is not more than 5 lbs. 7 ozs. (ii) That the strength of material and attachments throughout the lamp is not less than in the samples submitted for Official test on 16th February, 1928.

(iii) That the lamp shall be capable of maintaining a light of not less than one 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 arc of 45 degrees in a horizontal plane..

(iv) That the lamp has been made at the Works of Svenska Ackumulator Aktiebolaget Jungner, Frensgatan 3, Stockholm, Sweden; and that the accumulator has been made at the Hunt End Works of Batteries Limited, Redditch.

(v) That the integral parts of each lamp as issued by the maker namely, the case, cover, accumulator and lamp-bulb, shall have marked upon them the name or distinguishing mark of the lamp; and that the case shall also bear the name of the maker.

(2) FEDERATION LAMP COMPANY (WM. MAURICE), STAR WORKS, SOUTH STREET, PARK, SHEFFIELD.

"Federation" 4-volt Lamp.

This lamp, details of which are shown in Plate 5 comprises the following essential parts:

(1) Square case of tinned or cadmium plated steel, containing a 4-volt accumulator. A brass ring, welded to the case, is provided with a screw thread engaging with a loose screwed brass ring, which retains the accumulator in position within the outer case. The brass ring is also provided with an external screw thread, which engages with a screw thread on the cover or lantern.

(2) 4-volt accumulator of the lead-acid type with flat plates contained in a square celluloid case. The plates are secured to an ebonite cover by means of nuts which screw on to the lugs of the electrodes, the series connection between the two cells being embedded in recesses moulded in the cover. The cover is held in position by the loose screwed ring which also holds the accumulator in position within the outer case. Connection with the lamp-bulb is made by means of concentrically placed brass contacts embedded in the ebonite cover. The capacity of the battery is not less than 8 ampere hours with a voltage drop to not less than 3-6. The electrolyte is semi-solid.

(3 Cover or lantern of hard aluminium alloy, or alternatively of brass, mak ng a flame-tight connection with the case, and carrying an insulated bras contact plate upon which is mounted the bulb-holder. Concentric