July 10, 1914. THE COLLIERY GUARDIAN. 81 When the device illustrated in fig. 1 is placed in the open bell-jar and exposed to the atmosphere, no index movement is observed; but, when the operation is re- peated, though with an air pressure within the bell-jar, an indication occurs. With the double-chamber instrument a much shorter movement is observable, but with the absorption - methanometer no such change takes place; in fact, it is an advantage to force the test air in under pressure from a pump, thereby greatly increasing the absorption effect. Fig. 7 shows an alternative method of collecting sam- ples of the atmosphere by upward displacement into the chambers, the air travelling downwards if it be purer, and therefore heavier, than the surrounding mine air. Results of Tests.—Some of the instruments illus- trated in the paper were tested at a Yorkshire colliery in gas estimated by a tester’s lamp at a 1| per cent, mixture of methane and air, in the presence of a con- sulting engineer and mine undermanager and a deputy. The results are tabulated as below :— Description of instrument and fig. number. Dimensions of collective chambers. Per cent, of methane. Difference in level of fluid index. Time allowed for indication. Remarks. No. 1.—Brass instrument with holes underneath admitting the atmosphere from between figs. 13, 14 and 15 1 x | if I in. 1 minute Reading comparatively low due to shape of holes. No. 2.—Aluminium instrument with revolving cover similar to figs. 7 and 8, but with diffusion media removed t x H if re in. 1 minute Increased reading due to greater capacity and long narrow chambers. No 3.—Tap form, figs. No. 10 and 11 i x 1 if I in. 1 minute The methanium being placed above the collection chamber instead of within them as other instruments. In order to ascertain more accurately the behaviour of the instruments they were carefully tested in pit gas drawn from the Cymmer Colliery in South Wales in the following manner :—• A bell glass of 5880 c.c. capacity was fitted with a rubber stopper carrying an air circulating fan operated from without the glass, a thermometer, and a sensitive U-tube manometer. The pit gas was admitted at slightly above atmo- spheric pressure from a specially contracted gas receiver. The effect on the manometer and thermometer of adding 10 per cent, of gas were inappreciable. In addition to the three instruments referred to in the preceding table, instruments illustrated figs. 2, 5, and 6 were also tested in various percentages of pit gas in the following manner :— Experiments with varying temperatures and pressures were also made. It was discovered that by injecting the pit gas with a rubber syringe the extent of the readings were almost doubled. Description of instrument and figure numbers. Measured per cent, pit gas and air. Measured per cent. CO2 and air. Difference in index level. Tempera- ture difference. Time for reading from immersion in gas after closing chamber. Remarks. m/m. Degs. Secs. Single chamber non-c »mpensating — — 5 + 2 5 instrument. Fig. 2. Interior 5 — 10 5 in. — 15 2 in. by 1 in. 2 -— 4 — 15 1 — 2 — 15 — 5 7 + 1 6 — 2 2 + 1 10 Turquand compensating single ( Results about same as above ; excepting that no indication occurred even when chamber instrument. Figs. 3 and < heated up 10 degs. (owing to my tube compensating device). Readings 4. Same dimensions as fig. 2. C would be controlled by varying the details of the instruments. Absorption instruments. Figs. 7 10 — 50 — 30 and 8. 5 — 20 — 30 2 — 5 — 30 2 — 8 — 30 1 Atmosphere in- 1 — 4 — 30 ) jected with syringe. Figs. 9 and 10. (Tap form) 10 — 40 — 30 5 — 15 — 30 2 —; 6 — 30 1 — 1 — 30 Figs. 7 and 8. After exposing the 10 — 10 — 30 ) Atmosphere methanium to air for 10 mins. 5 — 4 — 30 £ injected with 2 — 1 — 30 ) syringe. Figs. 7, 8, 9 and 10 — — — 15 30 , 120 | Under pressure 3 in. mercury. These experiments could be carried further to discover the rate of deterioration of the methanium, but the safer plan is to use a number of small, cheap instruments for one reading only if as much as 5 per cent, is indicated, and to then renew the catalytic material. Shipments of Bunker Coals.—During last month 1,681,477 tons of coal, etc., were shipped for the use of steamers engaged in the foreign trade, as against 1,721,016 tons in June 1913, and 1,561,215 tons in June 1912. The aggre- gate quantitv so shipped during the first half of the present year has reached 10,182,157 tons, as compared with 10,087,037 tons and 8,125,897 tons in the corresponding periods respectively of 1913 and 1912. The Price of Petrol.—At the beginning of the present week petrol was reduced in price to Is. 8d. per gallon for the best grade, and to Is. 6d. for the second quality. This is the first reduction for some years. In 1905 the price of petrol was 7d. a gallon; from that time it rose steadily, until in the early part of last year it was Is. 9d. It has remained at about the same price since then, until the present reduc- tion. THE SENGHENYDD PROSECUTION. The hearing of the summonses against the owners and the agent of the Senghenydd Colliery, namely, the Lewis- Merthyr Consolidated Collieries Limited, and Mr. Edward Shaw, the manager, was concluded at the Caerphilly Police Court on Saturday. There are altogether 21 summonses for alleged breaches of the Coal Mines Act, 1911, and the prosecution is the result of the Home Office enquiry into the Senghenydd disaster, which occurred on October 14 last, and resulted in the loss of 439 lives. The magistrates were Mr. W. Ware (chairman), Mr. C. E. Forestier Walker, and Mr. D. Prosser. Mr. Ivor Bowen, K.C., with Mr. Albert Parsons and Mr. Clem Edwards, M.P. (instructed by Messrs. Vachell and Co.), prosecuted for the Home Office. Mr. Charles Kenshole defended, Mr. Ivor Parry (Messrs. Walter Morgan, Bruce, and Nicholas) watched the proceedings for the Miners’ Federation, and there were present Mr. W. Brace, M.P. (the president), Mr. James Winstone (the vice-president of the Federation), Mr. Alfred Onions, Mr. Hubert Jenkins, Mr. Tom James, and others. The first cases dealt with were two summonses against Mr. Edward Shaw charging him with neglecting to system- atically clear the floor, roof and sides of the roads under section 62, subsection 3, of the Act. Mr. Ivor Bowen, in the course of his opening, said that it had been admitted at the enquiry that the explosion was caused by gas fed by coal dust. The Bench had nothing to do with the cause of the explosion, but they had to consider whether there had been breaches of the regulations under the Act. It had been decided by the High Court in 1885 that the words “ as far as practicable ” must be construed from the physical and engineering point of view and npt from a profitable point of view. A view had been taken which was not accepted by the prosecution, that the words “ as_far as practicable ” must relate to the latter part of the section of the Act. The owners or agents were bound to systemati- cally clear the mine of dust, whatever the effect of the clearing might be. Mr. Dyer Lewis, H.M. inspector of mines, gave evidence relating to the admission made by Mr. Shaw at the enquiry, and in reply to Mr. Kenshole, he said that if the dust was brushed, it might be the cause of greater danger if it was blown into the faces. Dr. W. N. Atkinson, divisional inspector of mines, said it was quite practicable to carry out the section and have the dust removed by compressed air, but he did not think it would be effective, and in certain circumstances it might increase the danger. If there had been no Act of Parlia- ment, and he had been in charge of the mine, he would not have advised this to be done. Replying to Mr. Bowen, Dr. Atkinson said that if com- pressed air whs used, and if there were stone arches well watered between that place and the faces, the danger would be removed, for the coal dust would be caught in the wet zone. Experiments were now being made in that direction, and he believed they were satisfactory. Mr. Hugh Johnstone, H.M. inspector of mines for the Midland and Southern Division, examined by Mr. Clem Edwards, said the mines in South Staffordshire were deep, fiery, and dusty, and operations were being carried on to prevent the accumulation of dust, by watering and by stone- dusting and brushing. Sometimes the sides and roof and timber are swept down with a wet brush. Commencing at the pit bottom, they washed with the air current in every case. This prevented accumulation. The coaldust deposited varied very much in fineness. Some was as fine as flour, but when swept it did not follow that it all went in the ventila- tion. The heaviest particles fell to the ground. It was im- possible to absolutely clear the dust, but it was possible and practicable to so clear up the dust as to prevent accumulation. Witness thought this could be done at Senghenydd with com- pressed air, and he did not agree with Dr. Atkinson that the dust would find its way to the working places. He did not think the danger from dust would be increased. Replying to the magistrates the witness said that if the mine was systematically cleared of dust, the danger would be diminished. Mr. Thomas Henry Mottram, H.M. inspector of mines for Yorkshire and North Midland, agreed with the evidence of the last witness and said that the process of laying stone dust had'been effectually used in his district for the removal of dust, and he believed the coal dust could be cleared from the sides and roof at Senghenydd without going to the faces. The stone dust thrown on the sides brought the coal dust to the floor and then it could be taken out of the colliery easily. Mr. Charles Robinson, another inspector of mines, who had had 14 years’ experience in Monmouthshire and part of Glamorgan, said he saw no reason why the coal dust should not have been cleared at the Senghenydd Colliery. The brushing process was perfectly practicable, and the better cleared were the sides and roof the less would be the danger. Apart from stone dusting he believed Senghenydd would' be safer if the sides and roof were systematically brushed. Replying to Mr. Kenshole, witness said he knew of no coal mine in Monmouthshire where the sides were brushed. Mr. Kenshole, for the defence, submitted that the question of stone dusting was irrelevant to the present charge, as it was simply a question of adopting means to clear the coal- dust. The learned counsel had made a most astounding proposition—that the owners were bound to clear the floor, roof, and sides, whatever the effect may be. This he sub- mitted was not the meaning of the section. The proper interpretation of the Act was that the places should be systematically cleared so far as practicable, so as to prevent coal dust accumulating. Mr. Shaw, in his evidence, said that in his efforts to clear the mine of coal dust the question of expense had not entered at all. Arching had been tried, but the squeeze crumbled the arches; then dusting was tried, but four men could only clear 150 yards at a time, and the dust was driven forward from one section to the other, and by the time the men had cleared 300 yards there was such an accumulation of dust in the section already dealt with that attention had again to be given to this section. Cross-examined, he said he was now experimenting with coal dust, and had set up a system of sprinklers on the main road. When they dusted the roads he found that the dust was carried in suspension to the faces 600 yards away, and it might be carried a mile. In his opinion, with sufficient men and sufficient water and sufficient money the dust could be prevented from being deposited, and could be brushed away, but he would not adopt such a remedy, for it would be dangerous to the men working beyond. Mr. David Hannah, Ferndale, the eminent mining engineer, was the next witness. He spoke of the excessive danger attendant upon the clearing of dust from the roof and sides by means of compressed air. Such clouds of fine dust would be raised that it would be impossible for any men to work beyond, and there would be great danger of suffoca- tion. It could only be attempted on week-ends, and then it was not very effective. Mr. Thomas Griffiths, Cymmer, another expert mining engineer, agreed with Mr. Hannah and gave the experience gained since the Senghenydd explosion by a committee appointed to enquire into the question of the removal of coal dust. They found that by clearing the fine dust the greater quantity of it was deposited in the coal faces, having been carried in suspension in the air current. In one colliery in one year 120 trams full of coal dust had been carried in the current to the fan drift, but there would be far more deposited on the way and in the working-places. In cross-examination, witness said that section 62 (3) could not be carried out in the Senghenydd mine. Mr. Bowen said there were three more summonses against Mr. Shaw dealing with alleged neglect to provide a book and to enter the records of the measurements of air 100 yards from the working places. Evidence having been given, Mr. Kenshole argued that these measurements had only to be made once every month after the Act came into operation, and there was no obligation upon the company to measure under the new regulations until October 16. Three summonses against the company were next dealt with for allowing safety lamps of non-approved types to be used in the mine, for failing to provide the necessary books, and failing to provide means for reversing the air current. In reply to the last of these, Mr. Shaw said that he had had a consultation with Mr. W. T. Rees, the managing director, with reference to the scheme to be adopted, and once this had been agreed upon the whole thing was left in his (Mr. Shaw’s) hands. The directors knew nothing at all with regard to the question of the provision of approved lamp glasses, nor the measurements.of the air. Mr. W. T. Rees, the managing director, gave evidence to the same effect, and Mr. Kenshole, at considerable length, argued that the company had taken all reasonable means to enforce the provisions of the Act, and that the summonses against them should be dismissed. The Bench intimated that their decisions on the various summonses would be given at a special court to be held on July 18. “ Syren and Shipping ” Empire Number.—We have been favoured with a copy of the special Empire number of Syren and Shipping, which contains over 200 pages of interesting matter. Amongst other items, we notice a nice illustration of the C.P.R. Galt coal mine, Lethbridge, Alberta. There is also a striking portrait of Lord Aber- conway on the front page; and amongst many special articles, we notice “ The Oil Resources of the Empire,” “ The Shipping Problem at Calcutta,” and “ Geared Tur- bines or Diesel Engines,” as more particularly appealing to our interest.