162 THE COLLIERY GUARDIAN. July 28, 1916. had largely altered that state of affairs. Plant for the manufacture of colour on a scale never hitherto attempted in Great Britain was being erected as fast as possible. Research also was being organised on a scale hitherto not attempted, so that the neglect of research might not in future be counted against the British firms as one of their sins of omission. In fact, when the colour consumers of this country came to weigh the efforts which had been made for them by the staffs of the colour firms of this country, they would be amazed at the success of those efforts. The task before the British industry was inestimably difficult, because the Germans had formed a huge combination, with 11 millions pounds sterling capital, to fight the British efforts, which at first they treated with contempt. This opposition was most formidable, being formed of the cream of the German colour firms, with 40 years’ experi- ence behind them. Nevertheless, the British chemist was being given a chance for the first time to fight the German chemist with anything like equality of oppor- tunity. Speaking for his own colleagues, they welcomed the fight, in order to show that British chemists were equal to German chemists. He had little doubt but that the other chemists engaged with other firms do so like- wise. In the past the British firms fought in a very antagonistic atmosphere, in the cultivation of which some scientific societies were not free from blame. Let them have a sympathetic atmosphere in future; let authors who read papers on colours illustrate their experiments with British colours. They would find samples just as readily furnished by British firms as by German firms. What the British industry required was sympathy and patience—the handicap of 40 years was sufficiently heavy to warrant it. If they must have criticism, do not let it be destructive, but constructive —criticism founded on knowledge. Papers were also read on “ The Shale Oil Industry,” by Mr. D. R. Steuart, and on “ The Extraction of Tar Fog from Hot Gas,” by Mr. G. T. Purves. APPROVED SAFETY LAMPS. (Continued from page 65.) Part II.—Electric Safety Lamp approved for general use Messrs. Teale’s No. 1 Miners’ Electric Safety Lamp. This lamp, the general design of which is shown in fig. 5, possesses the following essential features :— (1) A case of steel, brass, or aluminium, provided with a securely riveted or soldered brass screwed locking ring. (2) An electrical accumulator, the terminals of which are fitted with rigid springs carrying rubbing brass contacts. The construction of the accumulator is such as to prevent escape of the liquid whatever the position PLAN AB. ALTERNATIVE CONTACT PLATES. PLAN A B. SHOWING CONTACT PLATES .8 D HALF ELEVATION HALF SECTION. PLUG LOCK SECTION C.D. MAGNETIC LOCK Fig. 5.—Teale’s No. 1 Electric Lamp. of the lamp, whilst allowing the escape of the gas generated by chemical action. (3) A cover forming a flame-tight connection with the case, and consisting of a middle base ring of brass or steel carrying an aluminium or steel crown supported by four or more brass or steel pillars. The middle base ring is screw-threaded internally to take a fibre, wood or glass retaining plate. A stout protecting glass forms flame-tight connections with the crown and retaining plate by washers of asbestos or other suitable material. The glass retaining plate also carries the lamp-holder and an insulated electrical contact piece. (4) An efficient locking device securing the cover to the case, consisting of:—(a) a lead rivet lock, with a hinged hasp or lug securely attached to a sliding band on the cover, and a staple or lug securely attached to the case; (b) a vertical lug lock; or (c) a magnetic lock as shown in fig. 5. The total weight of the lamp must not be more than 51 lb. The strength of material and attachments throughout the lamp must be not less than in the samples submitted for the official tests on July 28, 1915. The lamp must 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 arc of 45 degrees in a horizontal plane. The lamp must have been made at the works of Messrs. W. E. Teale and Co. Ltd., at Sindsley, Swinton, near Manchester, and must be marked with its name and the name of the maker. Part III.—Amendments to the Schedules to Previous Safety Lamps Orders. Electric Safety Lamps. All approved electric safety lamps shall conform to the following requirements, and the description of each lamp is amended accordingly :— (a) No celluloid, xylonite, cr other material liable to be ignited by the spark on making or breaking contact or on short circuit shall be used in proximity to the terminals; Provided that as regards lamps taken into use in mines on or before December 1, 1915, this require- ment shall not come into force until January 1, 1918. (b) The use of terminals which can be bent over, such as flexible spring terminals, is prohibited. Messrs. John Davis and Son (Derby) Limited. In the description on pages 10-13 and pages 38 and 39 of the Safety Lamps Order of August 26, 1913 (St. R. and O., 1913, No. 886), of the approved safety lamps made by Messrs. John Davis and Son (Derby)* * * § * Limited, the words “or not” shall be inserted after “ strengthened ” in the paragraphs relating to the gauzes. Mr. J. H. Naylor, Central Brass Works, Wigan. (a) All approved lamps made by Mr. J. H. Naylor, Wigan, may be made to take glasses 66^ mm. (± |mm.) in height, and may be fitted with the typ- of gauze fitting shown in fig. 6. (b) The types of electric igniter shown in fig. 7 are approved for use with the approved safety lamps made by Mr. J. H. Naylor. Each igniter must be securely fitted so as not to cause the lamp to be dangerous in an explosive Fig. 7.—Naylor’s Electric Igniters. Fig. 6.—Gauze for Naylor Lamps. atmosphere, and the strength of each igniter must be not less than that of the samples submitted for the official tests on September 15, 1915. The type of igniter shown in the sectional elevation of the full lamp in plate 14 of the Safety Lamps Order of August 26, 1913,f is no longer approved. Messrs. J. H. Rothwell and Co., Swinton, near Manchester. The Middle Rings of Co.’s “ A,” “ C,” and “ D ” lampsj may be pro- vided with additional horizontal air-inlet holes of total area not exceed- ing 0 7 sq. in., as shown in fig. 8. The strength of material and attach- ments throughout each lamp so modified must be not less than in the samples submitted for the official tests on September 22, 1915. Messrs. E. Thomas and Williams Ltd., Aber dare. In the description§ of the Cambrian Lamp No. 9 (a) The following pro- vision shall be added at the end of paragraph (1): This lamp may be fitted with a Mueseler chimney and glass extension, supported on a frame of brass or aluminium as in the Messrs. J. H. Rothwell and PLAN OF LAMP MIDDLE HALF ELEVATION j HALF_$ECTION Fig. 8 —Modified Middle for Rothwell Lamps A, C and D. case of the Cambrian Lamp * See Colliery Guardian, September 12, 1913, p. 525; October 24, 1913, p. 854. f See Colliery Guardian, September 26, 1913, p. 643. X See Colliery Guardian, October 10, 1913, p. 737. § See Colliery Guardian, August 7, 1914, p. 311. No. 1.* In lamps so fitted the dimensions of the Meuseler chimney are as follow :— In. Length of chimney above horizontal gauze, not less than 3 (wit ha cap 1 in. in diameter fixed jin. from the top) Length of chimney below horizontal gauze, - ot less than 7% Diameter at top .................................. Diameter at bottom ............................... 1 (b) No. (i.) of the conditions of approval shall be amended by the addition of the words “or on 29th July, 1915.” Messrs. Pearsons Electric Miners’ Lamp Co. Limited. The description^ of the Pearson Miners’ Electric Lamp shall be amended as follows :■—The total weight of the lamp is not more than 51b., and the lamp must have been made at the works of the late Messrs. G. Pearson and Sons Limited, at Al>bott-road, Poplar, London, E., or at the Victoria Works of Messrs. Pearson’s Electric Miners’ Lamp Co. Limited, Marshgate- lane, Stratford, E. * See Colliery Guardian, April 30, 1915, p. 911. f See Colliery Guardian, April 30, 1915, p. 910. WASTE IN COAL PRODUCTipN.* By Prof. Henry Louis. At a time when the subject of fuel economy is being brought so prominently before our notice, it is important to have before our eyes a complete review of each and every operation, connected with coal, in which waste occurs, and in which therefore the introduction of more economical methods is at any rate possible. The waste and losses connected directly with the getting of coal are by no means the least of the various forms of loss; and a clear conception of the nature of such losses is obviously the first step towards their avoidance. The coal output for 1913 is given by the Home Office as nearly 287J millions of tons, and it is important to note, firstly, how much of this total output is actually available for use by the nation at large, and, secondly, how much other coal has been sacrificed in order to obtain this output. In somewhat different words, the first item in the investigation refers essentially to the saving that could be effected in dealing with the coal after it had been brought to bank, and the latter to the saving that might be effected in the underground opera- tions of the colliery. Colliery Consumption. From the total output of coal there must be deducted the coal used for colliery consumption. Obviously a certain proportion of the coal raised in the country is consumed in raising it; in some districts, some or all of the colliers are supplied with free coal, which is some- times, though inaptly, included under the head of colliery consumption. The objection to the practice of giving free coal is that such coal as a rule is used very waste- fully; and if the men had to buy the coal and pay for it, more economy would be observed, and a considerably smaller quantity of coal be made to answer the purpose. The colliery consumption, i.e., the coal used in gener- ating the power necessary to work the colliery, can be ascertained without much difficulty. All well-managed collieries keep a careful record of their own consumption, and in some districts attempts have been made to obtain approximate statistics for the entire district. It would, however, need a proper enquiry backed by due authority to obtain figures for the country as a whole, because those collieries where the consumption is greatest will be the least willing to supply such figures. A certain amount of difficulty may arise from the fact that the coal thus used is of inferior quality, and not infrequently unsaleable. Within late years efforts to use inferior coal have been multiplied; and in some cases the whole of the power required to work a colliery is now being obtained from material which a few years ago was thrown on to the waste tip, and the use of inferior coal in gas producers is contributing to the extended employ- ment of such material. There is, however, still too great a tendency amongst colliery managers to consider that if pow’er is generated from an unsaleable material, there is but little need to exercise economy in its con- sumption. Such a view should not be allowed to obtain, and it has only arisen because the calorific value of the fuel consumed is too often disregarded, the money value alone being taken into account. Many collieries are so situated that they necessarily produce a certain amount of impure and dirty coal, the money value of which is less than the cost of marketing it, and the assumption is often made that such coal is therefore worthless. That it has, however, a very definite value as a fuel is shown by the burning pit heaps that may be seen in any colliery district. Definite information as to the quantity of coal burnt for colliery consumption is not obtainable, and a very rough guess is all that is possible at present. From personal observation, the author is inclined to think that the colliery consumption of the country is about 7 per cent, of the output, or 20 million tons. It is evident that if groups of collieries would combine to erect central gas producer plants, using low-grade coals, from which power could be distributed to the various pits within a reasonable radius, the saving that could be effected by the utilisation of the by-products and by the substitution of inferior for better class coal would amount to a very large annual sum. Utilising Coal Dust. In many districts vast quantities of fine coal dust accumulate in the screening plants, and lie there until cleared out and thrown away. Such coal dust is in many cases quite fine enough to be used direct for firing boilers or furnaces, and is well adapted for this purpose; it could be readily and cheaply cleaned and graded by * From a paper read before the Society of Chemical Industry.