178 THE COLLIERY GUARDIA1L ■ January 26, 1917. CURRENT SCIENCE Economy of Pulverised Coal. Between Chicago and Milwaukee the Chicago and North-western placed in service, over a year ago, a passenger locomotive equipped for burning pulverised coal. It has been thoroughly tested in active service, and has demonstrated a marked saving in fuel. According to tests published in the Railway Age Gazette, this locomotive evaporated 13 per cent, more water per pound of coal and consumed 18 per cent, less coal on the runs between Chicago and Milwaukee than was required with a similar locomotive fired with lump coal in the ordinary manner. Moreover, a much cheaper grade of coal was used on the locomotive burning pulver sed coal. In firing up the cold locomotive only 7501b. of powdered coal were required, as against 1,700 lb. of lump coal. But an even greater point in favour of powdered coal is the ability to shut oft* the fire entirely while standing still. Thus, the fire can be entirely shut oft for about half an-hour, yet in five minutes after it is started again the boiler is up to full pressure. This saving in fuelwhile standing idle makes powdered coal particularly desirable for switching locomotives. The switching engines in the freight yards of cities and the engines that are getting up steam or standing with banked fires cause a very large part of the “ smoke nuisance ” that has been so greatly deplored in all large cities. The Protection of Iron and Steel. _A new coating process for iron or steel is described by Mr. H. Hess in Metallurgical and Chemical Engineering. Zinc is reduced to a very fine powder, containing very little oxide or other impurity. This is mixed with a suitable flux to the c< insistency of a creamy paste that is applied cold with the brush, by dipping or spraying. The metal to be protected is, of course, first cleaned, as it is for any method of protection. The article is then heated in any convenient way slightly above the melting point of the zinc. In order to secure a very tough and therefore ductile coating that will resist bending, twisting and hammering without cracking or splitting oft, tin and lead are added tp the pulverised zinc. The segregation found in large baths is absent, as the coat is very thin as compared with a bath. Nor can there be segregation as the coat is melted down, because the particles of zinc, lead and tin powder are separate and not alloyed as a rule; these particles are so small that the protective electro- galvanic action of the zinc extends to the adjacent lead and tin particles as well as to the iron or steel under- neath. The galvanised articles have more of the bright, smooth character of tin-plate than is the case with pure zinc. This method is equally useful whether employed initially for entire surfaces or whether used to repair damage in galvanised work, whether caused by time or in field assembly. The coat may be applied externally or internally, over whole surfaces or only to certain areas. The articles may be coated by being brush- painted with the cold epicassit, by spraying or by dipping. The application of heat has just as wide latitude; baking ovens, heated tumblers and the blast torch are used. Any of the softer metals that can be reduced to a fine powder are used as pure tin, pure lead, pure zinc and their mixtures in various proportions. The Lumen as a Measure of Illuminating Power. In a discussion of this question before the Illumi- nating Engineering Society, Prof. J. T. Morris defined the lumen as “ the flux of light received by a surface of 1 square font and having an illumination over its area of 1 foot-candle. The flux of light emitted by a source is 4 7f (12’57) times its mean spherical candle-power. Thus a 50-watt tungsten lamp operating at 0’8 candle per watt (i.e., 125 watts , per candle-power) yields approximately 500 lumens.” He stated that the American Illuminating Engineering Society had recom- mended the adoption of the lumen and that the makers of electric lamps contemplated adopting it. There were several advantages in using the lumen in connection with illuminating engineering calculations. For example, if the lumens in each zone from a lighting unit were tabulated, the addition of these values gave the total output of light—i.e., the total flux of light produced by the unit; this could be at once compared with the corresponding output in lumens of the lamp used in thelighting appliance (globe, reflecto*-, etc.), and the efficiency of : the latter readily ascertained. It was also convenient to work with lumens in the usual formulae for determining the average illumination in a room resulting from a given arrangement of lamps and particularly when the approximate average illumination over an area needed to be quickly determined It also facilitated calculation of the illumination derived from extensive illuminated surfaces, such as occurred in the case of indirect lighting. Mr. F. W. Willcox also spoke in favour of the lumen, because candle-power did not give any complete indica- tion of the actual quantity of light given by the iljuminant. ■ The fundamental requirement was a definite unit which would always clearly and invariably express one thing. This condition the lumen complied with and the candle-power unit did not. There were numerous varieties of candle-power: the mean horizontal, mean spherical, the upper mean hemispherical, and the lower mean hemispherical, the maximum candle-power values in different directions, and the “ apparent ” candle- power values obtained when a lamp was put in a reflector andthe light redistributed. Such complications did not arise.with the lumen. When employed either as a measure of luminous value or to express the efficiency of the illuminant, its terms were precise. Again, the unit of luminous values should not permit of manipu- AND TECHNOLOGY. lation by the alteration of its apparent value through change of the shape of the luminous body or through the use of any external accessories, such as reflectors, etc. Experience had shown that alteration of values by this means had been the chief defect of candle-power as a unit. The variation in candle-power values obtainable in different directions with different kinds and shapes of reflectors was well known. The same amount of light flux (lumens) was made to give—now 50, now 100, now 500 or more candle-power value. The speaker defined the lumen as the unit of the quantity of light flowing from a lamp or luminous source, the value established for the lumen being the amount of light from a unit source falling upon a unit surface, at a unit distance from the source—i.e., a lumen would give an intensity of 1 foot-candle over an area of 1 square foot. As each lumen corresponded to 1 foot-candle per square foot, the term “ foot-candles per square foot per watt” became more simply “lumens per watt.” The efficiency of the lamp was thus cleaily and fully measured by lumens per watt, instead of, watts per candle, and therefore the lumen was an all-round term of geneial application in lighting work. Furnace for Testing Refractories. Before a recent meeting of the Faraday Society, Mr. Ezer Griffiths and Mr. E. A. Griffiths described.a new electric furnace for testing the softening points and compressive strengths of refractory materials. The furnace contains a 12 in. sheet-iron casing, closed by two diaphragms of asbestos slate, a carbon tube 11 in. long, in. diameter inside, and | in. thick. To admit of temperature observations nearly the whole length of the tube is slotted, the width being | in. The tube is packed with crude zirconia, i.e., powdered baddeleyite, which begins to frit at about 1,100 degs. Cent. To prevent the formation of carbon, a layer of electrically- shrunk magnesia is inserted between the carbon and zirconia. Outside the zirconia is a layer of magnesia- asbestos lagging. Pressure is applied by means of a plunger arrangement, and, up to 150 lb. per square inch, is measured on a scale. The specimen is applied in the shape of a cylindrical rod, 1 in. long, f in. in diameter, placed between two carbon rods, with distance pieces of tungsten to avoid contact between the carbon and the refractory material. The metal parts are made of aluminium containing 20 parts of zinc and 6 of copper. The electrodes are two copper tubes, bent into zigzag form, and surrounded with white bearing metal, so as exactly to fit on the carbon tube without any need for machining the metal faces or grinding the end of the tube. The copper tubes protrude loosely through holes in the cover, and the carbon tube can then expand without straining any parts. With a current of about 400 amperes through the tube, the drop of potential across the contact is less than 0T volt. A neutral atmosphere of nitrogen is preferable to hydrogen, because the latter will diffuse through the hot walls. Current is obtained from a rotary converter and transformer. Temperatures are measured by the aid of a polarising type of optical pyrometer, the sighting on the specimen being slightly oblique so as to avoid small errors arising through radiation. The Telpher Conveyor in Gasworks. Mr. Gr. F. Zimmer (Gas World) recommends installa- tion of telphers in medium, and even small, gasworks, for which they offer the following advantages:—They receive the coal at the terminus of the gasworks (within or without its boundaries), whether this be a siding of a rail or water way, and deliver it either to the coal store or direct to the retort house; they reclaim the coal from the store and transfer it to the retort house; and they handle coke, hot or cold, from the retorts, pass it through some quenching process, and deliver it at the coke heap, and, conversely, remove it from the heap to other destinations, including transport to the terminus, for disposal in the same or similar trucks or vessels which brought the coal. A good example of a simple automatic telpher installation for a small gasworks is that in the Dutch town of Assen, erected to bring the coal from the canal about 130 yards away, with a busy thoroughfare between. The installation consists principally of a receiving tower of steel on the bank of t e canal, which has a projecting jib extension capable of being raised, in order to be out of the way of the traffic when not in use. The automatic telpher is fitted with travelling and winding gears, and is manipulated partly auto- matically and partly by a portable starter, which can •be used at different places by push-contact. When unloading'coal this portable starter is situated in the barge, and sets the winding gear of the telpher in motion to lower the empty skip into the barge. The attendant then replaces this by a full skip. The next starter movement causes the winch of the telpher to lift the load, and in its highest position the winch is automatically stopped, and the travelling motor is simultaneously started. The telpher now follows its track automatically into the coal store. On its way it passes a short portion of floating track, which is connected to an automatic weighing machine which records the net load of coal passed into the works. Just before the coal sheds are reached the track has a siding, and accoiding to the setting of the points the telpher proceeds into either off two coal stores. Wit I in these sheds the telpher encounters adjustable trippers which 'automatically tip the skips (which are ■suspended below their centre of gravity), and at the same time reverses the motor, so that the telpher starts immediately on its return trip tb the loading point quite automatically, and stops plumb over the barge, where the sime operation is repeated. . The length of the track is 240 yards, land the installa- * tion will handle nine tons per hour. Only three men are necessary. They fill the skips, replace the empty ones by full ones, and manipulate by starter the only motions which are not-automa tic. The saihe installation can be used to transport coke from the yard (over which the track passes) to the barges, where the skip ban be lowered to the. bottom of the barge before it is. tipped, to avoid breakage. Before the erection of this installa- tion outside labour had to be engaged for coal unloading, but with this plant the three men required can be spared from the permanent staff for unloading operations whenever required. An installation of a somewhat more extensive but yet similar character is used at the gasworks, at Bromberg, and has a capacity of about 12 tons per hour; but it can be much increased by the further addition of telpher units. The, amount of coal carbonised per annum is 17,500 tons, and the annual amount saved in labour, per annum, since the installation of the plant is about £1,000. These automatic telphers are . also used for the transport of coke, hot or cold. A system of coke quenching in connection with automatic telphers which is very simple and effectual is that of Illig. A large water receptacle, mounted on wheels and a rad-track, is placed by a hand-winch before the retorts to be drawn. Into this receptacle the perforated skip, of the telpher is lowered. The water enters the skip at the same time as the coke, the coke being thus thoroughly quenched, after which the telpher winch is started precisely as on all other occasions, only perhaps slower, so. that the surplus water may drain off. The coke has sufficient latent heat in its interior, if all has been properly timed, to dry by the time it reaches the heap. In some Cont nental gasworks in which this system has been in use for the last five years, skips which hold up to 800 kilos (that is, the contents from two retorts), and 18 such receptacles (from 36 retorts) can be quenched, conveyed and dumped on the heap in one hour. FIREMEN’S FEDERATION OF GREAT BRITAIN. The annual conference of the General Federation of Firemen’s, Examiners’ and Deputies’ Associations of Great Britain was held at Carlisle on Saturday, when delegates were present representing Scotland, Cumber- land, Northumberland, Durham, Yorkshire, North Staffordshire, the Midlands, Lancashire and Cheshire, North Wales, and South Wales. Mr. J. W. Sumnall, North Staffordshire, the president, occupied the chair. The general secretary (Mr. W. Frowen, South Wales) stated in his report that the Federation was making haste slowly, and that there was no reason to complain of want of recognition by Government departments. He also referred to the recognition of the Federation by various associations, remarking that the calling in for consultation of the president and secretary by the Lancashire and South Wales associations was a mark of fidelity to the Federation. Troubles and successes had been reported to the secretary by associations, and it was felt that there was a healthy belief in the need for the Federation amongst the various associations. The financial statement showed balance in hand of £50 odd. The conference expressed strong disapproval of the Home Office’s refusal to grant the same facilities to this Federation as tiny had to the Miners’ Federation in respect of the meeting called to deal with the output of coal. At the request of Lancashire the Federation discussed the question of the maximum number of shots a fireman or shot lighter should be allowed to fire in a single shift, and it was agreed to defer a decision. On the notice of the Yorkshire Association, the absence of uniformity in the various mining counties with regard to income tax as applied to colliery deputies was discussed, and z deputation consisting of the pi esir dent and secretary was appointed to wait upon the authorities at Somerset House. It was also decided to petition the authorities in favour of quarterly payments of income tax by firemen, examiners, and deputies. It was further resolved to seek affiliation with the Trade Union Congress. The Federation also resolved to persist in its demand for the right of representation upon national mining committees and scientific experiments conducted by the Home Office. A resolution was also passed approving of the formation of the English Wages Board of Deputies Association. Owing to the expense of attending movable con- ferences, it was decided to make Manchester the centre for all general meetings of the Federation; and in view of the increased railway rates it was also agreed to apply for permits to delegates to travel to all meetings in connection with the associations at a reduced rate. Bepresenfations were made about the alleged victim- isation of delegates to the conference, and it .was resolved to protest to the Government departments on the action of certain managements regarding this matter. Owing to the state of his health Mr. C. F. Bates (The National), resigned the treasurership, and Mr. J. W. Sumnall (North Staffordshire) was appointed to* succeed him. Mr. W. Johnson (Durham) was appointed piesi- dent; Mr. H. Gile (The National); vice-president; Mr. Frowen was re-elected general secretary ; and Mr.' Coulthard (Northumberland), Mr. Derbyshire (Lanca- shire and Cheshire), and Mr. Clai ney (Yorkshire) -were? elected the committee, in addition to the officers named, with Mr. W. McTrusty (Cumberland) as junior auditor. : Mr. A. Lymn, mining engineer, of Lower Ince, Wigan, has been placed upon the Commission of the Peace for the - County Palatine of Lancaster.