July 26, 1918. THE COLLIERY GUARDIAN. 179 week to week for their foundry coke, and some of them therefore prefer not to tie up with individual foundry interests, whose actual consuming rate, in these times, may prove more or less uncertain. In Connellsville a fair volume of business is done in spot coke from week to week in direct transactions. The market remains quotable as formerly: Furnace, 6 dols.; foundry, 72-hour selected, 7 dols.; crushed, over 1 in., 7-30 dols. per net ton at ovens. SOUTH WALES MINING TIMBER TRADE. The exploitation of home grown wood has largely in- creased the deliveries to collieries. The consumption of mining timber in South Wales during the past three weeks has not been so great, consequent upon the fall in the pro- duction of coal. Imports of foreign and Irish timber have been good, with the result that the chief collieries have larger stocks than was the case some months ago. The Allocation Pitwood Committee was formed s< me time ago to distribute pitwood more evenly amongst the various collieries and so obviate stoppages for want of timber. Recently, however, supplies of mining timber have been more abundant and several collieries have a fair margin available. Foreign Imports Good. The imports of foreign mining timber were satisfactory good supplies being received last week. The whole of the imports were from France, and the bulk of the supplies were taken by the Admiralty Pitwood Committee. Quota- tions were at the maximum scheduled levels, namely 65s. per ton ex ship South Wales ports for all sizes. The actual consignment received to June 19 were as follow:— Date. Consignee. Loads. July 13 Lysberg Limited .......... 3,000 „ 13 E. Marcesche and Co....... 120 „ 13 E. Marcesche and Co....... 108 „ 13 Lysberg Limited........... 720 „ 13 Lysberg Limited ........ 1,440 „ 15 Franklyn Thomas and Co.... ],250 „ 15 E. Marcesche and Co....... 270 „ 16 Lysberg Limited .......... 720 „ 16 Lysberg Limited ........ 1,920 „ 16 Lysberg Limited......... 1,440 „ 17 Budd and Co................ 42 „ 17 Lysberg Limited........... 720 „ 18 Matthew Thompson ....... 2,020 „ 18 Morgan and Cadogan....... 1,020 Total...... 14,790 Home Grown Timber. Cutting is proceeding well in Wales and the adjoining counties. All efforts are concentrated on felling and transportation, with the result that complaints have arisen as to the state of the land after the wood has been cleared. There is still a scarcity of labour, especially of hauliers, ,and the suggestion has been made of employing discharged soldiers. Imports for June. The imports of mining timber into South Wales and Monmouthshire during the past month amounted to 39,475 tons, which is below the maximum quantity allowed to be imported by the Government. The full quantity was probably not taken up owing to the heavier supplies of home grown timber available and, also to the lessened < consumption of mining timber arising from the fall in production. Average c.i.f. Prices. During the past month the average c.i.f price of im- ported mining timber received in South Wales amounted to 64s. 0|d. per ton. The maximum scheduled selling price is 65s. per ton, which leaves a gross profit of ll|d. per ton for importers’ remuneration, out of which, of course, expenses have to be deducted. The members of the Pit wood Importers Association some two months ago signed an agreement not to purchase French timber above 62s. 6d. per ton c.i.f. steamers, and 62s. 6d. per ton sailing vessels. This would secure to them a guaranteed remuneration for their services. The two firms composing the Admiralty Pitwood Committee are outside this agreement. Reafforestation of South Wales. A Cardiff Works Committee under the Whitley Scheme has put forward the suggestion that the Government should form a plan for the reafforestation of South Wales. It is urged that such a plan would create a considerable amount of work for discharged soldiers desirous of following an outdoor life. The waste lands of Wales could well be utilised for a system of afforestation. There are large tracts in hilly districts totally unsuitable for agriculture upon which larch and other useful trees could be grown. It is generally agreed locally that to be successful an affores- tation scheme would be best run under the aegis of the Government, which could insist upon a proper system of planting. Private enterprise is indifferent to the project, owing to the long time which must elapse before the capital expended yields a return. Miner’s War Wage.—The Coal Controller (Sir Guy Calthrop) met the executive of the Miners’ Federation at Holborn, on Tuesday, with reference to payment of the war wage for shifts, or part of shifts, worked by the men in case of emergency. The practice is to pay the-war wage of 3s. to the men for every day they work up to seven days a week, but the miners’ executive now asked that in cases where, owing to emergency, the men have to work longer than the eight hours shift an additional war wage of 3s. be paid for that emergency shift. The Coal Con- troller promised to give consideration to the application and give his reply next week. Miners’ Permanent Officials.—The executive of the Miners’ Federation of Great Britain, in resolving that their permanent officers, the president and secretary, shall give the whole of their time to the work, have decided that they must surrender any ambition to a Parliamentary career. They must not seek election to Parliament. The general expectation is that Mr. Robert Smillie, the present presi- dent, will be elected the first permanent president of the Federation. Mr. J. Robson (Durham) and Mr. Harry Twist (Lancashire) are candidates for the office of secre- tary. Mr. W. Straker, secretary of the Northumberland miners, who was nominated, decided not to contest the position, as it would involve his retirement from N or thumberland. CURRENT SCIENCE Effect of Load on the Refractoriness of Firebricks. In a report to the Refractory Materials Research Committee of the Institution of Gas Engineers (Gas World), Messrs. J. W. Mellor and W. Emery, after describing the furnace used for testing under load, state that with regard to the exterior and interior temperatures of bricks there is over 100 degs. Cent, difference between the interior and exterior of the brick on a three to fours heating, and also on a twelve to thirteen hours heating. The need for keeping the interior and exterior of the test piece at as nearly the same temperature as possible limits the size of the test piece. If the test piece be not greater than 1 sq. in. in sectional area, there are difficulties with pieces containing coarse grog, for such pieces are unduly weak mechanically. This is confirmed by the failure to obtain constant results under such con- ditions. Test pieces of 4 sq. in. section area were finally used. W ith these the temperature can be main- tained so that the interior is from 20 to 50 degs. Cent, less than the exterior temperature on a four hours heating. This determines the chief error of the ex- periments. The flux or matrix bind is quite different in the grog from what it is in the clay, owing to the fact that in the grog the fluxes of the clay have dissolved so much of the less fusible constituents that it is less fusible and more viscous than the flux in the original clay. When the clay and grog are fired together, the flux of the clay softens at a much lower temperature than that of the grog, so that the fluxes of the clay and of the grog do their work inde- pendently. Firebricks with coarse grog are liable to break down mechanically by diagonal shear, whereas with finer grog the collapse appears as if the actual fusion temperature is reduced, for the test pieces bulge. During the burning of the firebrick the clay does not get so good a grip of course grog as with fine grog. If a single specification test is to be prescribed for refractoriness under load, 50 lb. per sq. in. is too great. A smaller load would give clays with a higher softening temperature a better chance. The most in- structive test would be a curve showing the behaviour of the refractory unloaded, and with at least two different loads, but if one test is to be presented, a load of 25 lb. or 30 lb. per sq. in. will probably suffice. In general, the silica bricks stand up under load very much better than firebricks made from fireclays; but the finer grained silica bricks do not stand under load so well as the coarser grained silica bricks. Indeed, very fine grained silica bricks show as large a difference between the normal refractoriness and the refractori- ness under load as bricks made from fireclays. Firebricks under load seem to break down in two ways. In one type of collapse (fusion collapse) the firebricks gradually give way as the temperature rises, until finally the piece collapses. This behaviour is typical of aluminous and zirconia bricks. The break- ing down temperature indicated in the tables is not a definite temperature, but rather an arbitrary range of temperature during which the brick has sunk, say, i in. In the second type of collapse (mechanical collapse) the firebrick may show symptoms of a gradual deformation, but the characteristic feature is a more or less abrupt collapse. This is typical of silica and siliceous bricks, and, to a less degree, of magnesite and chromite bricks, although a sufficient number of varieties of the latter have not been deter-' mined to give the same confidence in making general statements. The effects produced are exceedingly complex, and they are affected by many factors other than compo- sition. The texture is one of the most important. As a first approximation, a firebrick can be regarded as a mixture of certain materials which are difficult to fuse with a more fusible constituent. During the firing of the brick the more fusible constituents form a matrix binding the other materials together. The matrix, particularly in the coarser grained materials, seems to determine the refractoriness under load. A red firebrick which collapsed under load at cone 3 did not collapse until cone 29—nearly 500 degs. C. higher—when under no load. In this case the matrix suddenly lost its binding power under the load. A firebrick fortified with silica grog may stand up under no load better than the brick without this grog, but with the load the ground mass gives way without being fortified by the grog. A few series of firebricks were made up in a known way from clays known to be good, and also from those known to be of inferior quality. Grog was made from the raw clay by mixing the clay with water, moulding approximately 8 in. cubes, drying and firing some to cone 10, some to cone 1. The fired blocks were ground and graded as follows: Fine passed through a 16’s riddle; medium remained on a 16’s riddle passed through an 8’s.; coarse remained on an 8’s riddle passed through a 4’s. In fifteen sets of ex- periments, increasing the size of grog had no specially marked effect on seven of the sets, it decreased the refractoriness of five of the sets, it increased the re- fractoriness in one set, and showed a maximum in two of the sets. The grain of the clay, the possible and actual deflocculation, is an uncertain factor, which will be taken up again in a subsequent report. In order to find if the firing temperature of the bricks has any influence on the refractoriness under load, some bricks were re-fired to cones 15-16 for two hours, and the bricks became more resistant. One series collapsed at cone 9 under a load of 50 lb. per sq. in. with bricks burned at cone 10, and the bricks collapsed at cones 14-15 when they had been burned at cones 15-16. This makes it probable that the flux, or whatever it is which binds the constituent parts of the firebrick together during the burning, is less viscous with firebricks burned to cone 10 than with firebricks burned to cone 16. It is probable that the fluxes during the burning of the brick are dissolving the less fusible constituents, and thus becoming more AND TECHNOLOGY. and more viscous. With firebricks burned at cone 10, these fluxes are still capable of dissolving more of the less fusible constituents; so that by thoroughly burn- ing the bricks at a high temperature the binding flux is stiffened, and the resulting firebrick is more re- sistant to refractoriness under load. MINING INDUSTRY AND MILITARY SERVICE. Bedlington Tribunal granted six months’ exemp- tion to a candle manufacturer, who stated that unless he was allowed to continue at his civil employment his works would close down. The miners were working under difficulties owing to the shortage of candles, and he claimed on that ground that his work was of vital importance. The magistrates at Ammanford Police Court had a case of importance to miners before them recently, a collier having been summoned as an absentee from the Army. His plea was that he was engaged at the Ammanford Colliery, and that as his name was not included in the list of the quota he was not liable to be called up. The National Service representative stated that he had called up the quota, and so far as he knew there was no agree- ment between the authorities and the Miners’ Federation in regard to a list. That was as to the first quota. In reference to the second, he had made enquiry, and was told that no arrangement had been made. There was absolutely no agreement whereby recruiting was to be confined to a ballot list. On behalf of the defendant, the checkweigher stated that the agreement between the authorities and the Federation was still in operation, and a letter was read to the Court bearing out this statement. A printed circular from the Ministry of National Service was also tendered, but the prosecuting solicitor objected to its being put in, as it was not authoritative. The checkweigher stated that it had been sent to every lodge in the country. Ultimately, the National Service repre- sentative agreed that if the men were handed over to him he would give them indefinite leave until it was found that the quota could not be supplied without them. Another case of interest is that of a collier at Tredegar who was before the Court a month ago, his case being adjourned until it could be ascertained what was the quota to be sent from the colliery at which he was em- ployed. The defence was that at the time the man was arrested it was not known whether a quota of 80 had been made up, and that if it had, the defendant would not have been an absentee. The prosecuting solicitor in this case stated that it was for the defence to prove that the calling-up notice was not in order. The Bench held that the notice was duly in order, and they therefore decided that the man was an absentee. In a letter, copies of which are now being circulated to the members of the Northumberland Mineworkers’ Federation, the Coal Controller refers to the scheme under which miners in medical grades lower than Bl are being returned from the Army to work in the mines, and states that a number of cases have been brought to his notice where men, instead of working at the mines, had gone into munition factories. This is quite contrary to the spirit of the Controller’s arrangement with the War Office. The Controller has no intention of confining the released soldier to the particular colliery for .which he was re- leased, although it is desirable that he should remain there. So long as the released miner continues to be employed in coal mining he will not, unless a national emergency arises, be recalled for service with the Colours, but if he should leave coal mining and enter any other occupation, then the whole basis of his release is at an end, and the miner will render himself liable to immediate recall to the Colours. At a special meeting of the Cumberland Miners’ Asso- cviation, at Workington, a resolution was carried, de- manding the release of all men who had been taken into the Army out of their turn in the ballot, or where more than the quota has been taken away from any pit, and that the matter be dealt with immediately. PARLIAMENTARY INTELLIGENCE. HOUSE OF COMMONS:—July 23. Prisoners in Mines. Mr. Hope informed Sir J. Butcher, in connection with the employment of British prisoners in German mines, that it was hoped the agreement concluded at The Hague would provide a satisfactory solution of the question. The agreement had not yet been ratified. Coal Supplies. Brigadier-General McCalmont asked whether it was the policy of the Coal Controller that all available coal should flow through the same channels as before. Mr. Wardle replied that since September last the prin- ciple of continuing available coal supplies through the same channels as previously had been in force so far as possible. Whether the available supplies of coal should go to the same customers as heretofore depended entirely upon the importance of the work the consumers were doing. Work vital to the conduct of the war must have priority. The position, however, was affected in regard to quantities as a result of the release of miners for the Army, increased supplies to Allies, plus the effect of the influenza epidemic. The attention of the Coal Controller’s representative in Ireland had again been drawn to this question. Raw Material Priority.—A number of leading repre- sentatives of trade, commerce and industry, and of indus- trial organisations established under the Whitley scheme, have been invited by Dr. Addison, Minister of Recon- struction, to attend a private conference to hear the Government’s proposals with regard to a system of priority and allocation of raw materials during the transitional period after the war. Purchase of Tar by Distillers.—A meeting of a com- mittee of representatives of the gas industry, appointed by the National Gas Council, and representatives of tar distillers was held recently to consider a scheme for the purchase of tar by distillers from gas undertakings. A joint sub-committee of distillers and producers has been engaged in endeavouring to arrange a scheme founded on the result of the negotiations entered into with distillers last year. The National Gas Council now reports that a satisfactory basis has been arrived at for a joint scheme. A further meeting of the joint committee is to be held.