THE COLLIERY GUARDIAN. June 1, 1917. 1034 REFRACTORY MATERIALS. The second ordinary meeting of the Refractory Materials Section of the Ceramic Society was held on May 21 and 22, at Stourbridge, under the presidency of Major H. C. King. SOUTH STAFFORDSHIRE CLAYS. Prof. W. S. Boulton, of Birmingham University, read a paper entitled “ The Clays of South Staffordshire and its Borders,” in which he described the various clays occurring in the district, especially those in the neighbourhood of Stourbridge. There is great variety in the clays of the districts, some of the fireclays merging imperceptibly into ironstones, calcareous clays into earthy limestone and sandy clay into argillaceous sandstone. A peculiarity is the almost complete absence of old red sandstone, carboniferous limestone and millstone grit, so that the coal measures rest unconformably on silurian rocks. The coal measures themselves correspond pretty closely with the coal measures of N orth Staff ordshire and those of East Warwickshire. Fireclays. After mentioning the coal seams, Prof. Boulton pro- ceeded to describe the fireclays, which also occur in seams, generally 2 to 5 ft. thick, and often as underclays to the coal seams. They are similar to the fireclays of the northern coal fields in being pale grey, brown or nearly black in colour, tough and unctuous, unstratified, and containing numerous rhizophores, or roots of sigillaria, lepidodendron and other lycopods, often with rootlets attached. The seams vary in quality and composition, and the same seam may vary from top to bottom as well as laterally. As a rule, the lower part is more siliceous than the upper; thus, the Old Mine fireclay is “ strong ” below, “ medium ” in the middle and “ mild ” at the top. The mild, or fat varieties, are comparatively free from sand admixture, while the strong and sandy varieties pass into ganister- like rock. They are all more or less refractory, some highly so, with a very low percentage of iron, lime and alkalis, and hence their use for making firebricks, retorts, crucibles and glasshouse pots. The most noted area for these fireclays is immediately east and north-east of Stourbridge and Old Swinford—round Lye, Amblecote, Brettell Lane, Brierley Hill, etc. Hereabouts the coal measures are gently folded into the north-east and south-west anticlines of Netherton and Lye and Stour- bridge, with a syncline between, so that the shafts within the anticlines enter fireclay measures below the Thick coal at a small depth, while in the synclines the brick clay group above the Thick and Brooch coals has to be passed through before the fireclays are reached. The district is also traversed by a number of faults. The Old Mine fireclay can be traced over the whole district, usually 3 to 5 ft. thick. In the Stourbridge district no coal seam is found immediately above the Old Mine fireclay, but elsewhere a coal seam or less perfect indications of carbonaceous material occur. Between the Old Mine fireclay and the uppermost of the New Mine fireclays No. 1, the measures vary from 30 to 60 ft. New Mine fireclay No. 1 is persistent over the whole district, and is 3 to 6 ft. thick. The measures between the New Mine fireclay No. 1 and New Mine fireclay No. 2 range from 20 to 54 ft. in thickness. New Mine fireclay No. 2 is present in all the pits. Below New Mine fireclay No. 2 the co-relation of the fireclays is uncertain and difficult. In a coal measure series the coals are the most per- sistent strata when followed laterally. Where underclays accompany the coal seams, they, too. are very constant, but some coals have no underclay, nor are the under- clays always fireclays. The Stourbridge fireclays are not associated with coal seams, although indications of carbonaceous matter (smuts, etc.) occur in places. Moreover, it is clear that the fireclays, without coals, are very much more constant in this district than in the intervening measures, which change in thickness and character. As regards the origin of fireclays, the commonly accepted view is that they are the original soils upon which the coal measure vegetation flourished, and that the iron, lime and alkalis have been extracted as food for the vegetation. But in the Stourbridge district the absence of vegetable remains (as coal) in situ makes it probable that the Stourbridge measures were deposited as sediment under estuarine conditions, the fireclays representing the fine silt, or ooze, very slowly but continuously deposited. STEEL FURNACE REFRACTORIES. Mr. W. J. Brooke, of the Shelton Steel and Iron Company, Stoke-on-Trent, read a paper on “ Refractories for Steel Furnaces from the Consumer’s Point of View.” He referred at some length to defects met with in silica bricks, and the variations, in some cases apparently unaccountable, which came under his notice. Practi- cally, every grade of silica brick is inferior to what it was three years ago. Silica Bricks. Excessive expansion of silica bricks may generally be traced to imperfect drying of the bricks before burning, or to insufficient burning, or both. “ Running,” or complete fusion of the bricks, evidenced on the walls and blocks of a furnace, as a very pronounced “ smear,” and in the roof or crown as “ icicles,” always causes friction between the furnace manager and the manufacturer. Carelessness in the manipulation of the furnace occurs, and the remedy is clear. But defective bricks also occur, and the remedy is not so obvious. The fault is associated with a comparatively low percentage of silica in the brick, but not lower than in other bricks found to be good. It will usually be found that in the latter case the difference is made up with alumina, whilst in the former it is made up by excess of lime used as bond. Softening and breaking away in lumps is very often shown in a roof. In one very bad case a furnace had, from this cause, to be put off for repairs after about two weeks working. Analysis of the bricks showed 96'2 silica, 2'13 lime, 0'31 alumina, 0'49 ferric oxide, 0'15 alkalis, with a trace of magnesia. The texture of the bricks was very coarse, with an admixture of very finely-ground body as a bond. The bricks were made from a very pure quartzite containing about 98 to 99 per cent, silica. It was eventually ascertained that the makers, in an emergency, had used this material in place of their usual ganister, which required a minimum of foreign admixture to make a good brick, and was found to give good results when gi ound coarse. The same, procedure was adopted with the new material, limewash being added to give the usual proportion of lime. The coarse grinding had the effect of disturbing the balance of the proportions of main body and binding material, and the more fusible bond melted and carried the more refractory material with it. “ Spalling ’ is probably always due to improper burning of the bricks, whether the texture be coarse or fine, the analysis perfect, and everything apparently good. Spalling is caused by incomplete inversion, and in a similar (though reverse) manner to the spalling of magnesite bricks, as described by Dr. Mellor. Reference was made to the fact pointed out by Prof. Arnold that the steel furnace at Sheffield University might be available for testing bricks. The author contends that hundreds, of brick-testing furnaces are in daily use, and if it be urged that furnace managers are too busy to bother about testing other people’s products, he replies that if it should seem likely that an improvement in the product would result, the importance of the subject would gain ready co-operation from them. What was needed was the collaboration of the maker, the consumer and the scientist, and the author suggested that all steel manufacturers and refractory brick makers should become members of the Ceramic Society, and also contribute to a research fund. The plant of some steel works might be placed at the disposal of the society for carrying out such tests of raw material or manufactured product as might be necessary, such tests to be supervised by representatives of all three interests. The tests would, of course, be graduated and performed with proper safeguards. Under such a scheme makers could submit samples to the scientist, who could advise as to the testing. The results would at first be communicated only to the maker. Suggestions were made as to the carrying out of certain tests in steel furnaces. The author went on to criticise silica bricks as regards size,.shupe, &c., and stated that it might readily happen that something like 15 per cent, of a structure could be cement and 85 per cent, of brick, the consequence of which, he said, would be serious. Magnesite Bricks. Magnesite bricks also came in for much criticism, the author laying stress on the necessity for burning them at a much higher temperature. He admitted that British magnesite bricks were improving, which he attributed largely to the researches of Dr. Mellor. He hoped here, too, the user might be taken into consulta- tion with the manufacturer and scientist. DISCUSSION. Mr. W. J. Jones, of the Ministry of Munitions, pointed out that British manufacturers of silica bricks had been working under stress. Since .the war com- menced 66 per cent, more silica bricks were being made. Also the men who got the ganister joined up, and their successors lack their experience. He cordially agreed with Mr. Brookes’ suggestion respecting close inter- course between makers, users and scientists. The effort should be national and concerted—say, one co-ordinated centre, with Dr. Mellor presiding, and other centres at Sheffield, Glasgow, South Wales, Birmingham, &c., each to investigate a different question. LETTERS TO THE EDITORS. The Editors are not responsible either for the statements made, or the opinions expressed by correspondents. All communications must be authenticated by the name and address of the sender, whether for publication or not. No notice can be taken of anonymous communications. As replies to questions are only given by way of published answers to correspondents, and not by letter, stamped addressed envelopes are not required to be sent. HOUSE OF COMMONS AND SAFETY HARNESS. Sirs,—Re the discussion in the House of Commons, when Sir George Cave acknowledged that proper shaft- men’s safety harness (or rigs) were not in common use, and shaft fatalities had decreased in consequence, the answer is hardly full enough. However strong may be officials’ desire for safety, and however willing commercial managers may be to provide “ proper appliances ” (Rule 38), the present indefiniteness of the law tends to aid the argument of shaftmen who are not willing to obey official orders. They are apt to argue that safety appliances are not necessary, because such are not specifically named. This is the point that needs legal alteration—the pro- vision of appliances competent to safeguard shaftmen against their risks. The law need not deal with usage, time, place, or method, as these are matters that develop gradually. So long as the law is definite, and stands behind officials on whom it puts responsibility, other aspects would settle themselves. This would cut out cases of injury which now occur at pits where proper appli- ances are not provided. A. Hanley. May 26, 1917. Mr. Henry Peile, of the Priestman Collieries Limited, has been re-elected chairman of the Newcastle section of the Society of Chemical Industry. Second-Lieut. C. H. P. Jackson, of the 1st Royal War- wicks, has had a most strenuous time since he went to the front in May of last year. His name appears in Sir Douglas Haig’s despatches for distinguished service. Second-Lieut. Jackson is the son of Mr. C. F. Jackson, of The Gables, Bedworth. The young officer has a brother, Lieut. Jackson, in the Machine Gun Section, and another who is a cadet in H.M. Navy. APPROVED SAFETY LAMP GLASSES. In pursuance of Section 33 of the Coal Mines Act, 1911, the Home Secretary has made an Order approving certain glasses until further order, for use in any flame safety lamp of approved type. The Order may be cited as “ The Safety Lamps Order of the 14th May, 1917.” The following are the particulars of the glasses referred to:—Glasses bearing the trade marks shown below must be made in the sizes specified. In any the variation in thickness must not exceed 1mm., and in any one size of glass the variations in external diameter and height must not exceed it mm' } an<^ ± | mm. respectively. The ends of the glasses must not be out of parallel to an extent of more than | mm. The dimensions are to be indicated by numerals on each glass. Brand :— External diameter, 55 to 6 7 mm.; height, 55 to 67 mm. thickness, 3’5 to 6 mm. Makers: Messrs. Stevens and Williams Limited, Brierley Hill Glass Works, near Stourbridge. Brand :— u HAILUXO ” External diameter, 55 to 65 mm.; height, 55 to 70 mm.; thickness, 4 to 6 mm. Makers : Messrs. Ackroyd and Best Limited, Morley Glass Works, near Leeds. MINERS’ PERMANENT RELIEF SOCIETIES. The CentralAssociation of Miners’ Permanent Relief Societies held the annual conference on Tuesday in the Imperial Hotel, Russell-square, London. Col. R. E. Martin (chairman of the Midland District Miners’ Fatal Accident Society) presided. From the report of the consultative committee, it appears that 3,825 widows and 3,530 children are now chargeable on the general fund—a decrease of 170 widows and 236 children. The following figures for the past year and for 1915 were given: — 1916. 1915. Increase. Membership ............ 286,187 ... 267,294 ... 18,893 Members’ contributions. £269,536 ... £246,014 ... £23,522 Revenue ............... £304,250 ... £281,227 ... £23,027 Accumulated funds ..... £883,359 ... £882,743 ... £616 The committee expressed gratification that the Northumberland and Durham Society have decided to increase their contribution Id. per week, to pay an extra 3s. per week to their superannuated members, except those who are in receipt of State old-age pen- sions, for the duration of the war and six calendar months thereafter. Reports of quinquennial valuations of several societies were quoted. The West Riding of Yorkshire reports three separate valuations of incumbents to be made. Two valuations for incumbents on the old scale fund disclose a surplus of £1,594 (widows and children) and a deficit of £1,249 (permanently dis- abled members) and a surplus of £3,752 (new fund)— due to the contributions being fully adequate, and the society’s experience having been upon the whole finan- cially favourable. The valuation report of the Mon- mouthshire and South Wales Society for the five years ended 1915 discloses a deficit in No. 1 account (old fund) £36,887, and in No. 2 account (scheme fund) a deficit of £13,295. The chief causes of the heavy deficits shown are loss of revenue sustained by the society as a result of the withdrawal of the employers and workmen from membership, and in consequence of the board of management being compelled, in order to meet current payment of relief to the large number of recipients on the funds, to realise the society’s invest- ments on a very largely depreciated money market. Mention was made of the fact that since the Central Association was formed, in 1878, to December 1915, the organisation had dealt with 1,715,877 disablement cases, as well as 17,101 fatal accidents, bringing upon the funds 11,077 widows and 20,530 children. The report stated that the consultative committee had con- sidered the proposed extension of the relief fund move- ment to districts where no such organisation exists. The Miners’ Federation of Great Britain had declined the suggested co-operation for extending the relief fund movement, on the ground that it was outside the scope of the Federation, and was a matter for the districts to deal with. Mr. Hibbert (Lancashire) said that these figures ought to lead to the establishment of relief societies in districts where none exist at present. Only 30 per cent, of the working miners in the country were members of relief societies. Mr. Darlington said that it was not reasonable to expect the State to make provision for dependants in the event of fatal accidents. It was for the individual himself to make due provision during his lifetime. Mri Sewell thought that some scheme might be evolved by which the State, owners, and workers would be contributors. Mr. Booth (Yorkshire) remarked that the workers would themselves make the necessary provision by join- ing relief societies if the owners would, with the men’s consent, allow weekly subscriptions to be stopped out of the men’s wages at the office. In some districts the owners would not sanction this, and in those districts the societies were weak. It was decided to empower the consultative com- mittee to take up propaganda work in those districts where no relief societies exist, and to ask the com- mittee to approach the owners with the view of furthering the aims of the relief societies.