710 THE COLLIERY GUARDIAN. April 5, 1918. interior thereof a space or chamber g around the outlet orifice e, thus shutting off the outlet-valve d from direct communication with the interior of the helmet a. The additional outlet-valve h, which is fitted to the partition f, is connected to the mask b by the pipe I and opening into the chamber g. With this construction, as will be understood from the foregoing description, the wearer inhales, through the valve c, the fresh air delivered by the pump through the valve c1 into the cavity of the helmet a, and he exhales through the valve h into the chamber g, the used or vitiated air and any excess air being discharged into the surrounding water (or into the atmosphere in the case of a smoke helmet) through the ordinary valve d. The outlet-valve h, instead of being attached to the partition /, as described and illus- trated. may be directly secured to the mask or mouth- piece b, the tube i in this case being fitted at its other end to a connection on the partition. In some cases a second flexible or rigid chamber may be interposed between the outlet-valve of the mask or mouthpiece and the chamber g, the object of this additional chamber being to render the expiratory effort easier under certain circumstances, or this additional chamber may be attached directly to the chamber g. This improved apparatus is designed to be used in combination with divers’ helmets or smoke helmets or in divers* bells, submarine boats, etc., and that it may be used either with apparatus supplied from a pump or other source of supply from the surface, or with self-contained apparatus in which the wearer carries a supply of compressed air. (Three claims.) 112793. Improvements in the Distillation of Coal, Oil Shales, etc. 8. B. Bilbrough, Marshall-square Buildings. Holland-street, Johannesburg, Transvaal.—In the present practice of distilling coals, oil shales, etc., in vertical retorts, the gases and vapours, containing the volatilised tars and oils, are drawn off or removed by a pipe positioned at the top of the retorts, and after passing through condensers, wherein the vapours are condensed to oils, etc., are separated from the non-condensable gases and water in washers. By distilling coals at a low tem- perature—about 500 degs. Cent.—the yield of tar oils per ton of coal distilled is very much increased, and the volume of gases decreased; also the character of the oil distillate obtained is different at low temperature distillation to what it is at high temperature distillation. The reason usually assigned for this increased yield of tar oils, and the different characters of same, is that the vapours come into contact with the surfaces of the retort walls which are at a comparatively low temperature, and at which temperature the vapours are not decom- posed or altered, as they undoubtedly are when the retorts are heated to a full red heat, say, i000 degs. Cent. The vapours by coming into contact with the surfaces of red hot walls of the retort are decomposed, forming an increased yield of gas, and consequently a decreased yield of oil. To overcome this difficulty or defect, and to increase the yield of tar oils from coal, it has been proposed to lower the temperature attained in the retort to about 500 degs. Cent., or even 450 degs Cent., and as a consequence of this comparatively low temperature system of distillation the yield of tar oils is increased by a large amount, about 50 per cent. The principal disadvantage of low temperature distillation is that the process is very slow, as it takes about four times as long to carbonise a ton of coal at 500 degs. Cent, as it would at 1000 degs. Cent., other conditions being the same. Another disadvantage is that it is not so easy to make a good hard well-binding coke from a suitable coke- yielding coal in retorts at the low temperature, as the coke or product then produced is much more friable than if such coal had been subjected to a full red heat in the retort. In order to obviate these two serious dis- advantages, it is proposed, according to this invention, to distil the coal ,or oil shale preferably in the usual vertical retorts at the usual temperatures of from, say, 800 degs. to 1200 degs. Cent., and at the same time prevent the vapours or distillate from coming into contact with the hot walls of the retorts. This result can be attained, for example, by inserting a central tube into the body of the coal being carbonised in the retort. This central tube has suitable perforations, holes, or openings, down its length, and the gases and vapours, as soon as they are formed or generated from the coal by the heat, immediately travel to the nearest opening in said central tube, pass up the tube, and are drawn away to the foul main and condensers. It will be understood that the central tube never becomes very hot, for the reason that it forms a core in the centre of the coal bed,, and is the point furthest away from the source of heat, i.e., the hot walls of the retort. The time requisite to carbonise coal or shale in a retort equipped with the central tube or passage is very much shorter than in one without it, as the heat has a much shorter distance to. travel in the former than in the latter case. Also, by using the central tube, there is no core, as the central tube occupies the place of the core, with the result that the carbonisation is more complete. (Seven claims.) 112856. Improvements in Coal Cutting Machines. T. Guy, No. 4, Evelyn-terrace, Doncaster-road, Barnsley. —This invention relates to coal cutting machines of the chain type provided with means for removing the debris from the gap in the coal seam left after the passage of the chain cutter, and consists in an improved arrange- ment of the debris removing device travelling parallel to and to the rear of the cutting chain and driven from d'x the driving shaft operating same. Fig. 1 is a plan view of a chain type coal cutting machine fitted with a scraper device according to this invention. Fig. 3 is a left hand side elevation of the same. The scraper device comprises an endless travelling chain a, passing round two sprocket wheels b, c, and fitted with a series of scrapers d, Motion is imparted to the scraper device from a sprocket wheel e fitted on the coal cutter, by means of a chain /, which also engages the sproket wheel g fixed on the same shaft as the wheel b. The scraper device is rigidly connected to the coal cutting machine by a plate h. It will be observed from fig. 3 that the sprocket wheel b is on a slightly higher level than the sprocket wheel c. This ]s so arranged in order that the debris w’hich is carried forward by the scrapers d may be propelled up the slightly inclined tray i and deposited through the hole j therein on to the ground clear of the face of the seam. It is desirable to have as much clearance as possible between the underside of the tray i and the ground, but this has to be arranged according to circumstances as it involves a slightly oblique drive of the chain. Sometimes it is feasible to have the scraper device running in a perfectlv horizontal plane, in which case the speed of travel would have to be such that the debris would be thrown clear of the machine by centrifugal force as the chain and scrapers passed round the sprocket wheel b; the tray i could then be dispensed with. The scrapers d are pro- vided with spike extensions or cutters d' which serve to break down any upstanding or depending projection of coal or rock left by the cutters of the machine. Metal cover plates k, k1, are fitted underneath and on top of the scraper device. (Three claims.) HEW PATEHTS CORRECTED WITH THE COAL ARD IROH TRADES. Applications for Patents. March 25 to 30 (inclusive). Ashcroft, E. A. Carbonisation of coal or distillation and cracking of shales, peat, oils, pitches, etc. (5502) Bamford, J. E. D. Fire-grate. (5212) Bingham, C. Blast furnaces. (5261) British Westinghouse Electric and Manufacturing Com- pany. Electric transformers. (5241) Brown and Company, J. Steam turbines. (5210) Clifton, AV. E. Electromotors. (5216) Constantinesco, G. Method of pulverising or atomising liquids. (5487) Constantinesco, G., and Haddon, W. Liquid wave trans- mission of power. (5488) Cooper, T. L. R. Pumps. (5454) Coupler Limited, A. B. C., and Mitchell, J. Couplings for railway, etc., vehicles. (5505, 5506) Crooke, A. Systems of electrical distribution. (5314) Dale, Brown and Company. Gas-producers. (5333) Dewdney, G. F. Internal-combustion engines. (5424) Fletcher, J. E. Furnaces. (5548) Goodwin, A., and Huntingford, E. S. Tractors for over- head runways. (5470) Hayhurst, W. Centrifugal pumps. (5308) Helps, G. Gas manufacture. (5526) Jenkins, E., and Thorpe, J. Rotary pumps. (5339) Jones, J. Indicator and safety device for winding- engines, etc. (5554) Lamplough, F.. and Oil Extractors Limited. Distillation of coal. (5511) Leeming, J. A. Aerial ropeways. (5486) Marshall, T. S. Rotary engine. (5558) Mitton, W.,and Vaughan Crane Company. Overhead tracks of trolly hoists or telphers. (5521) Morgan, H. R. liiternal-combustion engines. (5306) Newall, J. C. Gas-producers. (5333) Price, J. Steam generators. (5552) Rigby, W. F. Skip. (5341) Ripley, A. S. Engine to generate steam for its own pro- pulsion. (5361) Royle, G. E. and J. J., and Royles Limited. Feed-water apparatus for steam boilers, etc. (5524) Ryan, A. S.and M. J. Anemometers. (5430) Salfeld, C. S. Internal-combustion en gines. (5438) Schmidt, K. Smelting furnace heated by oil or gas. (5227) Smith, P., and Varley, G. P., Rotary pumps, fans, or blowers. (5545) Soc. Franco-Beige de Fours a Coke. Horizontal coking ovens. (5328) Thomas, G. H., and Wilkinson, G. S. Internal- combustion engines. (5304, 5306, 5307) Thomson, J. C. Indicator and safety device for winding engines, etc. (5554) Thomson, T. Systems of electrical distribution. (5314) Thompson, J. L. Electric transformers. (5241) Warburton, F. T. Method of drying peat turves. (5559) Wilde, A. H. Internal-combustion engines. (5307) Wood, W. H. Steam turbines. (5210) Complete Specifications Accepted. (To be published on April 18.) 1917. 700. Snell, C. Scott- Apparatus for compressing gas or air. (114165) 2344. Constantinesco, G. Pumps. (114170) 2477. Rainey, F. E. Water-tube boilers. (114172) 3746. Hall, I. Furnaces. (114177) 3947. Thompson, AV. P. (Reilly, P. C.). Preservation of wood, and the production of substances there- for. (114181) 4053. AVhite, W. A. Liquid fuel furnaces. (114188) 4115. Perfecta Boiler Circulator Limited, Ayers, P. C., and Josling, H. AV. E. Means for promoting the longitudinal circulation of fluids in steam generators and other tubular heating apparatus. (114194) 4191. Honegger, G. Expansion gear for duplex steam pumps. (114200) 4244. Dear, H. A. Manufacture of fire-lighters. (114201) 5255. Marks, E. C. R. (Soc. Franco-Beige de Fours a Coke). Regenerators for coke ovens. (114222) 5352. lonides, A. C. Gaseous fuel furnaces. (114223) 5759. Haddan, R. (Commercial Research Company). Rotary furnace structures. (114228) 7184. Perry, F., and Metalloids Limited. Manufacture of iron. (114237) 7767. Briggs, H. M. Fuel economiser or false grate. (114240) 9327. Ludwigsbergs Werkstads Aktiebolag. Rotary pumps or engines. (107596) 9383. British Thomson-Houston Company (General Electric Company). Electric motor control. (114,246) 12601. Coleman, A. B. Hand tools or appliances for facilitating the making of- block fuel or briquettes. (114264) 14326. Guy, J. G. Endless rope haulage clip. (114272) 17989. Smithey, AV. D. Means for generating and storing power by the compression of air. (114,286) 1918. 723. Peterson, J. Power generating devices. (114290) Complete Specifications Open to Public Inspection Before Acceptance. 1918. 4633. Industrie-en Mijnbouw-Maatschappij Titan. Smelt- ing titaniferous iron material. (114309) 4959. Deutsche Gasgluhlicht Akt.-Ges. (Auerges.). Method of determining the quantity of steam flowing through a pipe. (114313) 5006. Siemens-Schuckertwerke Ges. Purifying water in boilers, etc., and appartus therefor. (114314) Restoration of Lapsed Patent. Notice is given that James Todd has made application for the restoration of Patent No. 15593 of 1909 for “ Improved fastenings for smoke-box doors of tubular boilers or the like,” which expired on July 5, 1915, owing to the non-payment of the Renewal Fee. Opposition to the restoration should be lodged at the Patent Office, on or before May 27, 1918. Utilising Fuel Waste*—The Bulletin des Usines de Guerre reports an experiment on the utilisation of the combustible matter in boiler clinker. On the assumption that the 25 tons of coal consumed daily furnish 5^ to 6 tons of clinker containing about 25 to 30 per cent, of combustible matter, a small washing plant was installed at a certain French works, to treat this clinker, with the result that about a ton of combustible was recovered per day. Only two men were required for the work. The quantity of fuel recovered was 20 to 25 per cent, of the waste treated, or 4 to 5 per cent, of the original amount of coal. 1 a I Telephone- 687 Centra! Telegrams- 6 6 Octagon, Sheffield, Neepsend Rolling Mills, SHEFFIELD, MANUFACTURERS OF OCTAGON, ROUND & CRUCIFORM TOOL STEEL; COAL-CUTTER PICKS, files, hammers, drills, &c„ so.