November 6, 1914. _______________________________________________________________________________________________ THE COLLIERY GUARDIAN. 971 (c) Dock or Harbour Walls. — Hydraulic machines have been used for some years at the Dover Harbour Works for the purpose of detaching the large concrete blocks used in the harbour walls. Machines are being used for a similar purpose in other docks. Excavation of Foundations. — The question of the removal of concrete foundation beds by a method which would not involve explosive blasts, and would avoid the slightest damage to machinery or buildings, has been carefully studied recently by the writer, and had never been thoroughly solved until extended trials in all parts of the British Isles had been made. The effect of powerful hydraulic pressure upon con- crete is interesting. In the case of sandstone and shales there is comparatively slight crushing of the rock before the full pressure of the rams has the effect of causing the mass to bend; considerable pumping and consequent travel of the rams is then necessary before the rock finally begins to crack and break away; with concrete, however, there is usually a perceptible interval during which the rams are crushing or compressing the material, and no movement is noticeable; after this is accomplished a -few more thrusts of the rams cause the whole mass to break up without any indications of bend- ing. It may still be necessary to continue to apply pressure and to increase the size of the breaks in the mass, but the greatest shattering effect will have been accomplished at the first disclosure of the cracks, the pressure required to break the mass afterwards gradu- ally diminishing. In such material, explosives invariably have the effect of “ hacking a way through ” by the shortest direction to the unsupported edge, pulverising the mass, but fail- ing to take advantage of pressure gently applied,, by means of breaks which spread and widen, and to utilise the weight of the concrete itself to increase the scope of the operation. Numerous experiments in this class of work show that 60 to 70 cu. ft. of concrete can be easily removed per thrust. The general procedure in attacking beds of concrete may be divided thus :—(1) By vertical cartridge holes; (2) by horizontal cartridge holes. There appears to be no class of work so suitable for this machine as the removal of concrete beds. At a municipal electricity works a whole bed weighing approximately 200 tons of concrete was removed in 20 working days. About 60 shots were necessary to com- plete the work, making an average of nearly tons per thrust. The cost of the work was as follows :—Labour per day, including operator, drillers, navvies, and fore- man, £2 15s.; amount of material removed (average 10 tons per day), 4s. 9d. per ton. ____________________________________________________ LAW INTELLIGENCE. ___________________________________________________ SCOTTISH COURT OF SESSION. FIRST DIVISION.—October 29. Before the Lord President and Lords Johnston, Mackenzie, and Skerrington. Workmen’s Compensation : Industrial Disease and Prior Employment. Merry and Cuninghame Limited v. M. M‘Gowan.—Judg- ment was given in an appeal by Merry and Cuninghame Limited, coal masters, Auchenraith Colliery, Blantyre, in an arbitration under the Workmen’s Compensation Act, in which Michael M‘Gowan, miner, 107, Stonefield-road, Blan- tyre, claimed compensation. While working in Dechmont Colliery in April last year the respondent received an injury to his knee, and while incapacitated received compensation. On January 27 last he entered the service of the appellants, and on the following day found his eyes troubling him, and he did not work after that date. Subsequently he was certified as suffering from miners’ nystagmus, and his dis- ablement commenced on January 28. Sheriff-Substitute Hay Shennan awarded compensation, holding that the disease was in part due to the nature of the respondent’s employment during the 12 months preceding the date of dis- ablement. The Division dismissed the appeal, and found the appellants liable in expenses. The Lord President said that where a disease which dis- abled a workman was presumed to be due to the nature of the process in which he was working at the time, he was entitled to have compensation exactly as if on the date of disablement he was the victim of personal injury due to an accident arising out of and in the course of his employment. As the respondent’s last employers they were liable, but it was competent to them to demand that the compensation be shared by every person who during the preceding 12 months employed him in mining. The other judges concurred. ____________________________ The 51st ordinary general meeting of the Concrete Institute will be held at Denison House, 296, Vauxhall Bridge-road, Westminster, S.W. (close to Victoria Station), on Thursday, November 19, 1914, at 7.30 p.m., when Prof. Henry Adams, M.Inst.C.E., M.I.Mech.E., F.S.I., M.S.A., &c., will deliver his presidential address. The following particulars relate to the United States coke industry in 1913:—Establishments, 551 ; ovens built, 102,650 ; ovens building, 1,321; coal used, 69,239,190 short tons ; average yield in coke, 66*9 per cent.; coke produced, 46,299,530 short tous ; value of coke, 128,922,273 dols.; average value per ton, 2’78 dols.; coke exported, 987,395 tons. Of the total production of coke, 33,584,830 tons, valued at 80,284,421 dols., were made in beehive ovens, and 12,714,700 tons, valued at 48,637,852 dols., in by-product or retort ovens. The output of retort coke in 1913 exceeded that of 1910 by over 5,500,000 tons, or nearly 80 per cent. .The following was the value of by-products imported into the United States in 1913 :—Salicylic acid, 2,969 dols.; alizarine and colours or dyes, natural and artificial, 1,493,840 dols.; aniline salts, 323,420 dols.; coal tar colours or dyes, 7,253,788 dols.; coal tar preparations, not colours or dyes, 702,721 dols. ; coal tar products, other than medicinal or dyes (benzol, toluol, &c.), 1,186,090 dols. THE IRON ORE DEPOSITS OF EASTERN AND WESTERN FRANCE.* By Paul Nicou. Now that France has become—during the last few years and owing chiefly to the development of the calcareous ores of the Briey ore field—one of the principal ore-exporting countries, it will soon become a matter almost of necessity for the leading ore-importing countries to arrange to secure a share of the output in proportion to their respective requirements. Belgium has become practically dependent on the Lorraine ores, and in 1912 received from Meurthe-et- Moselle 4,351,00.0 tons out of a total of 6,415,000 tons, or 67'8 per cent. Whatever the future may, however, bring forth, the imports of French ores into the Zollverein have now actually almost attained to an equality with those from Sweden, and have ex ceded those from Spain, the two countries which, for a long time past, have shared the German market. In 1913 they reached 3,810,887 tons, as against 4,558,362 tons and 3,632,058 tons from these countries respectively. The large interests acquired more or less recently by powerful German or Luxemburg companies in the Lorraine and Normandy ore fields; the reduction from frontier stations onwards of the freight charges for the con- veyance of ores towards Westphalia ; and the possibility of employing in the latter route both rail and canal transport, with transhipment at Givet, cannot fail to increase the part played by France in the supply of the works in the Zollverein. To S’lo Maltot To Paris •Ondefbntaine Quesnoy Lesson To GranotUe Conde s/ Noireau .Tiers 20 te fteufbi Brtouze lomfronl 11 To Lanai To Ale/t^ons "agerre dafonte ^Patrice du ) Desert 1 SLAndre Z May 3 Bully <► Maltot 5 Orville Z.Gouvtx 7 Barberj 15 Halouze 16 taFernere 17 Larchamp 18 Mont en (>er5/ne \38ourberouge 20 Mortain ie Chateht Stffomer 8 Perrieres 9 Soumont 10 Is trees taCampagne 11 S? Remy 12 Jurques 13 Monipinqon l