1216 THE COLLIERY GUARDIAN December 22, 1916. tugal, with 980 torus, ranking next in importance. Central South America, Australia, and the Malay Penin- sula were other regions which afforded appreciable per- centages of the world’s tungsten supply. Vanadium sources, as known at present, seemed mostly to be in the hands of the United States. Peru, which produced 3,000 tons of 40 per cent, vanadium ore in 1912, had lately been the only commercially important source oJI high-grade vanadium ores, but the vanadium impregnations in the Great Baisin range district of Colorado and Utah were worthy of note. Cobalt was recovered as a by-product during the smelting of the silver ores mined about Coleman, in Ontario, about 100 tons of cobalt metal being exported from Canada in 1915. Molybdenum was found among vein stones, and was mostly separated from gangues mainly exploited for their tungsten ores. Queensland, New South Wales, and South Australia together sent about 150 tons per year of molybdenite to be smelted. Norway also supplied a little, and Canadian mines were now beginning to produce. The subject of the supply of sands for steel moulding was one in which there was urgent need for correlated scientific and industrial research. Among minerals used as abrasives, 'the 37 thousand tons of emery exported from the islands and countries adjoining the 2Egean Sea had held the predominant posi- tion. Corundum, obtained by crushing and separation of igneous rock at various places in Ontario (1,750 tons in 1912), in India, and in Madagascar, was also a material of increasing importance in the manufacture of abrasive wheels. The fact that an amount of metal equal to between one-fifth and one-quarter of the whole output of pig iron was imported as semi-manufactured iron and steel, to supply the British heavy engineering trade, must not be overlooked when the mineral supplies drawn upon by British iron and steel trades were being considered. In 1913, over 1,200 thousand tons of semi-manufactured metal came to us from Germany, as well as 585 thousand tons of similar material made up in Belgium. The importance of the Minette district, Lorraine, in supply- ing the iron ore from which the bulk of this metal was produced, was a matter which, in these times, should be emphasised forcibly and often. The British imports of smelted iron and half-manu- factured steel from Sweden in 1913 were 209 thousand tons; from the United States, 115 thousand; and from France, 42 thousand tons. Geology of Overseas Supplies. In dealing with the varied sources of this special material required for steel making, a brief note was included to explain the geological mode of occurrence of the important minerals. The author next proceeded to deal with the main overseas of iron and manganese ore in their turn, and in order that terms of every-day use among geologists might be intelligible to others, an introductory explanation was given of the more common geological conditions under which iron ore bodies occurred. The main part of the section was taken up with geological notes and descriptions of the ore fields which sent iron ore to British blast furnaces, or supplied ore which, smelted in foreign countries, was exported to this country as semi-manufactured metal. The ore reserves proved in each of the districts dealt with were noted, and the way in which each district described was likely to exert an influence upon British Had-' was discussed. Large iron ore reserves proved in districts which had not yet been drawn upon by British iron masters were also the subject of comment. For obvious reasons, no details were given concerning the reserves of ore awaiting development in this country. The immense potentialities for inter-trade between this country and her chief ally, France, if the produce of British coal fields could be bartered for iron ore, whether the Minette iron ore of the Briey plateau, in Lorraine, or the richer ores from the more accessible district between the English Channel and the mouth of the Loire, was specially emphasised. The relative inaccessibility and the difficulties and cost of transport consequent thereon which any scheme for supplying iron ore at the rate of several million tons per year, from British dominions, colonies, or posses- sions, must meet, was, said the author, a subject which needed no further comment. Supplies of pyrites, which, after roasting and suitable treatment for the extraction of spelter and more valu- able metals, were sent as “ purple ore ” to blast fur- naces, were also briefly dealt with; and some geological notes on the available supplies and the world’s reserves of manganese ores completed this section of the paper. Statistics. The statistical section of the paper, compiled by Mr. T. S. Ashton, formed a summary of summaries, and the author hoped that the graphs illlustrating the relative importance of iron ore production and steel production of Britain in its relationship to the various Continental countries during the pre-war decade, would arouse dis- cussion and be of permanent interest. Gas Coke for Boiler Furnaces. — The Deptford Borough Council has recently carried out experiments in the use of gas coke instead of coal as a fudl for boiler furnaces. A trial extending over four weeks was made with forced draught, as recommended by the London Coke Committee, from which the following results were obtained :—The total coke consumed in the four weeks was 81 tons 19cwt., at a cost of £110 19s. 6d. The price of the coke was 27s. Id. per ton, against 39s. 6d. per ton for the best steam coal usually consumed. The average quantity of coal consumed in the corresponding period for the three previous years was 67 tons, at a cost of £132 6s. 6d. This shows a saving, by burning coke, of £21 7s., or £5 6s. 9d. per week. The cost of the forced draught apparatus was £12 12s. APPROVED SAFETY LAMPS. In pursuance of section 33 of the Coal Mines Act, 1911, the Home Secretary has made an Order approving the following types of safety lamps, until further Order, for use in all mines to which the Act applies, subject in each case to the conditions specified in the schedule. The schedules to the Safety Lamps Orders of August 29, 1913, March 16, 1914, March 16, 1915, June 15, 1915, and May 15, 1916, shall take effect subject to the amendments set forth in Part IV. The Order may be cited as “ The Safety Lamps Orders of November 16, 1916.” Part I.—Electric Safety Lamps Approved for General Use. The General Electric Company's “ Kingsway ” Lamp. This lamp, the general design of which is shown in fig. 1, possesses the following essential features :— (1) A battery case of solid drawn steel (leaded), pro- vided with a threaded collar to receive the lamp cover. (2) A cover, comprising— (i.) A collar, which may be either a casting of brass or other suitable n on-magnetic material, arranged to screw to the case to make a flametight joint, or a steel stamping provided with a threaded liner to screw to the case. (ii.) A lock, which may be either magnetic, in which case the bolt is housed in an upward projecting boss on the collar; or a lead rivet, in which case a cross hole is provided through the bolt and the boss for the reception of the lead rivet. (iii.) A switch-plate, consisting of two parallel discs of vulcanised wood fibre, ebonite, teak, or suitable non-inflammable insulating material, the electrical connection between the plates being in the form of strong flat semi-circular springs which enable good contact to be made between studs on the lower face of the lower disc and the terminals of the battery. The switch-plate carries the socket for the bulb, and provides a bedding for the outer glass. Both switch - plate and outer glass are clamped in the head of the lamp by a threaded ring fitting within the collar. (iv.) A steel cap, carrying pillars and crown plate, to keep the enter glass in position if a dome-shaped glass is used. A cylindrical glass may be used, in which case the steel cap is not required, but the pillars and crown plate are fixed directly to the collar. FITTED WITH DOME GLASS Fig. 1.—The General Electric Company’s “Kingsway” Lamp. FITTED WITH CYLINDRICAL GLASS (3) An electrical accumulator, the terminals of which are solid fixed studs. The construction of the accumu- lator is such as to prevent escape of the liquid whatever the position of the lamp, whilst allowing the free escape of gas generated by chemical action. The approval is subject to the further conditions :— That the total weight of the lamp is not more than 6J lb.; that the strength of material and attachments through- out the lamp is not less than in the samples submitted for the official tests on January 20 and February 22, 1916; that the lamp shall be capable of maintaining a light of not less than 1 candle-power all round in a hori- zontal plane throughout a period of not less than nine hours, and also of giving a light of not less than 1*5 candle-power over an arc of 45 degs. in a horizontal plane; that the lamp has been made at the works of the General Electric Company Limited, at Witton, Bir- mingham. Messrs. John Davis and Son's ” Davis-Edison Accumulator ” Lamp. In this lamp, the general design of which is shown in fig. 2, the current is supplied by an alkaline secondary battery. The lamp possesses the following features :— (1) A stamped sheet steel case, fitted with screw thread for the attachment of the cover. (2) A cover of steel or iron, which screws on to the lamp case, and makes a flametight connection there- with. The cover is fitted with an internal switch-plate of ebonite, vulcanised fibre, teak, or suitable non-inflam- mable insulating material, and carries the lamp bulb and protecting outer glass. The outer glass is protected by a crown of steel or iron, supported by pillars of steel or iron mounted on the cover. Fig. 2.—“Davis-Edison Accumulator” Lamp. (3) An alkaline electrical accumulator, the case of which is of sheet metal, so constructed as to prevent escape of the electrolyte, whatever the position of the lamp; fitted with fixed spring terminals. (4) A magnetic lock, so constructed that the bolt can only be withdrawn by a powerful electro-magnet, or a lead rivet lock of approved type. The total weight of the lamp must not be more than 6| lb.; the strength of material and attachments throughout must not be less than in the samples sub- mitted for the official tests on March 8, 1916; the lamp must be capable of maintaining a light of not less than 1 candle-power all round in a horizontal plane through- out a period of not less than nine hours, and also of giving a light of not less than 1’5 candle-power over an arc of 45 degs. in a horizontal plane; and it must have been made at the All Saints Works of Messrs. John Davis and Son (Denby) Limited, Derby. Part II.—Flame Safety Lamp Approved for Use by Officials Only. Messrs. Thomas and Williams' Cambrian Officials' Lamp, No. 7. This lamp is a modification of the Cambrian Lamp No. 1 or No. 3,* and differs therefrom in design only in the heights of the gauzes and of the glass, which are as follow :— Gauzes— Outer gauze. Inner gauze. Height from shoulder of base ring ............ 3| in. ± 4 in. 3 in. ± | in. Glass— Height................. 57 mm. ± | mm. Size mark ............. E. T. W. 3. The lamp made be made of brass or of aluminium with pillars of brass. The gauzes may be of copper if the lamp is to be used for surveying purposes. The oil vessel may be fitted with a T7g in. flat or Jin. round burner, with or without an electric igniter of approved type. The strength of material and attachments throughout the lamp must not be less than in the samples submitted for the official tests on May 4, 1916; the lamp must be capable of maintaining a light of candle-power not less than 0’30,as determined by a pentane standard,all round in a horizontal plane throughout a period of not less than 10 hours; it must have been made at the works of Messrs. E. Thomas and Williams Limited, at Aberdare, South Wales; and must be used by officials only. Part III.—Pocket Electric Lamp Approved for Use by Officials Only, and Only in Conjunction with Another Safety Lamp of Approved Type. Messrs. Pearson's Officials' Pocket Lamp. This lamp, details of which are given in fig. 3, is intended to be carried in the pocket as an auxiliary light. It comprises a 2-volt accumulator in a locked casing, bulb, lens, reflector, and switch. The accumulator is so constructed as to prevent escape of the liquid what- ever the position of the lamp, whilst allowing the escape of gas generated by chemical action. The case and switch are flameproof. The lock is a lead rivet lock. The total weight of the lamp must not be more than 2| lb.; the strength of material and attachments throughout the lamp must not be less than in the *See p. 35 and pl. 27 and 28 of the Safety Lamps Order or August 26, 1913 (St. R. and O., 1913, No. 886).