812 THE COLLIERY GUARDIAN. April 19, 1918. atmospheric pressure or under a vacuum. According to this invention the necessary hydrocarbon oil is added to the core and the mixture is heated substantially as described in Patent 19750 of 1914. After a suitable time, for example, when the desired temperature has been reached, the pressure is released, and the distillation of the volatile matter is carried on either under atmospheric pressure or in a vacuum. 113200. Improvements in Centrifugal Compressors. The British Thomson-Houston Company Limited, 83, Cannon-street, London, E.C. (a communication from the General Electric Company, of Schenectady).—The present invention relates to centrifugal compressors, and has for its object to provide an improved impeller for such machines. Fig. 1 is a side elevation of a portion of an impeller embodying the invention, the entrance buckets of some of the blades being omitted to better illustrate the structure. Fig. 2 is a section taken on line 2—2, fig. 1 ; fig. 3 is a perspective view of a guiding and bracing member, and fig. 4 is a section taken on line 4—4, fig. 2. Referring to the drawings, 5 indicates a blade carrying member as a shaft having T-slots or dove- tailed slots 6 machined in it, into which are fastened the T-shaped bases 7 of a series of radial blades 8. This is a very simple fastening means for the blades, and at the same time a strong one which can withstand the centri- fugal stresses. Between the blades are fastened guiding and bracing members, comprising curved plates 10, prefer- ably formed of sheet steel and provided with flanges 11, which are riveted to the radial blades 8. In the present instance a double-sided impeller is shown, that is, one designed to take in fluid on the two sides and deliver it around the periphery, and two curved plates 10 placed back to back, as shown in fig.. 3, so that they curve in opposite directions, are accordingly riveted between each two blades 8. The curved plates 10 act as guides for the fluid being pumped, serving to direct it smoothly and evenly toward the periphery of the impeller, thereby giving the impeller a good efficiency. At the same time they bind all the individual blades together in a complete ring so as to guard against and prevent vibration of the blades. They also serve to give great stiffness to the impeller ; 12 indicates the entrance buckets for the blades 8. In fig. 1 of the drawing the entrance buckets 12 are omitted from the two right-hand blades for purposes of illustration, but it will be understood that all the blades may be provided fadth entrance buckets, although in some cases they may be omitted entirely. The entrance buckets 12 each comprise a base plate 13, on one side of which is a T-shaped projection 14 which fits into the end of slot 6. By this arrangement the same slots serve to hold both the radial blades and the entrance buckets. On the other side of base plate 13 is a wing 15 which curves forward in the direction of rotation, and which catches the fluid being pumped and directs it to the impeller. The peripheral portion of wing 15 is fastened to the adjacent blade by a pair of spaced lugs 16 which project therefrom, one on each side of the blade, and through which a rivet 17 passes. The centrifugal force acting on the entrance buckets when the impeller is rotating is considerable, and it is accordingly necessary that they should be firmly held. To insure this, the bases 13 .are arranged to overlap one with another, ds indicated at 18. This ties the entrance buckets together, and serves to secure the outer face edges of the wings. The direction of rotation is that indicated by the arrow, and it will be noted that the bases 13 overlap in such a manner that the edge of the base adjacent the outer edge of the wing laps under the next adjoining base. This serves to distribute the centrifugal force and renders the buckets mutually supporting. The above described impeller is comparatively simple in structure, light in weight, and cheap, to build. At the same time, owing to the arrange- ment of the parts, a very strong substantial structure is obtained. (Four claims.) — Aw,/J A\ 113246. Valve Apparatus for Rock Drills. G. H. T. Rayner, Grange Farm House, Carter Knowle-road, Abbey- dale, and P. Rayner, 38, Chantrey-road, Woodseats, Sheffield.—The object of this invention is to provide a simple and reliable rock drill valve which is very easy to construct and in which the moving valve part is of particularly light construction and inexpensive to manu- facture. Fig. 1 is a sectional elevation of a porticn of a rock drill fitted with the improved form of valve apparatus. Figs. 2 and 3 show alternative forms of valve discs. Fig. 4 shows the form of spring employed. Fig. 5 shows in outside elevation a port block. As shown in fig. 1, the piston p is moved to the right under pressure of air admitted at port «, and passing the valve disc v, through the channel b formed in the port block a1 and the cylinder wall, to the main cylinder c. As shown, the piston p has just passed the exhaust port e, thereby causing the cylinder c to come into direct communication with the atmosphere. A sudden reduction of pressure there- fore takes place on the left hand surface of piston p and the left hand surface of disc valve v, which moves to the left as soon as the total pressure on the left hand side of valve disc v has fallen to less than the total pressure exerted on the right hand area of valve disc v by the air admitted through port b2 plus the pressure caused by the forward movement of the piston p compressing the air in the right hand end of the cylinder after the exhaust port el has been passed, and forcing said air up the channel b1. As soon as the valve moves to the left the channel b is shut off from communication with the inlet a, and the channel bl is in full communication with the inlet air from port b2. Live air passes through channel bl to the right hand surface of piston p and returns the same to the left. When the piston p has passed the exhaust port ex an exactly similar cvcle of operations occurs in moving the valve to the right, to that just described. It will be seen that the valve v is formed as a simple disc of substantially greater diameter than thickness, which may be flat on both sides (as in fig. 1), or formed with concave or convex sides or seatings (as shown in figs. 2 and 3 respectively) to facilitate seating or “jointing” in or on the “beats” or por*t blocks through which the main ports to the cylinder are formed. The valve is steadied in its movement from side to side by a spring or springs s always under some compression, as shown in fig. 1. The springs s may be provided at one or both sides of the valve, and may, if desired, be of such strength as to appreciably influence the speed of travel of the valve in one direction or the other, or may be so light as merely to assist the valve to maintain an approximately upright position during its travel, and thereby prevent jamming and ensure quick and easy passage from one seating to the other. (Two claims.) 113671. Improvements in Rope Grips. A. Mackie, 32, Erskine-road, South Shields, and J. Mackie, 205, South Eldon-street, South Shields.—A rope grip made in accordance with this invention comprises an upper plate and a lower plate pivotally connected together, a jaw on each plate on one side of the pivot adapted to co-act to grip the rope, a segmental bearing surface on each plate on the other side of the pivot adapted to co-act to form an abutment for the jaws and to take the pressure off the pivotal pin; a shackle is disposed on the upper plate, and . the pivotal pin is provided with a tightening nut which is adapted to be held against rotation by an arm which may be connected to the shackle by a link. The pivotal pin is provided with a squared end where it passes through the bottom plate to prevent rotation.’ (Two claims.) MEW PATENTS CONNECTED WITH THE COAL AND IRON TRADES. Applications for Patents. April 8, to 15 (inclusive). [Note.—Applications arranged alphabetically under the names of the applicants (communicators in parentheses). A new number will be given on acceptance, which will replace the application number.] Alliata, G. Indicating arrangements qu furnaces for regulating combustion. (6175) American Sleeve Valve Motor Co. Internal-combustion engines. (6309) Anderson, A. Pulley blocks. (6093) Armstrong, J. E. Superheaters, and steam circulation therein. (6289) Armstrong, Whitworth and Company, Sir W. G., Legge, N., and Le Mesurier, L. J. Reciprocating engines. (6183) Benitez, C. Process for generation of electrical energy. (6131) Beswick, W. Gas generators or producers. (5974) Brush Electrical Engineering Company. Liquid resist- ances. (6256) Bynoe, F. O. Superheaters for air, vapour, or gas. (6024) Candy, H. E. L., and Lemoine, M. C. Damper for gas flues and mains, etc. (6028) Collette, L. Electric generators and motors. (6307) Crossley, Sir K. I., and Webb, W. Le P. Two-cycle internal-combustion engines. (5955) Crossley, Sir K. I., and Webb, W. Le P. Two-cycle internal-combustion oil engines. (5956) Crossley, Sir K. I., and Webb, W. Le P. Internal-com- bustion engines. (6091) Dickson, J. G., and Jones, T. A. System of electro- mechanical illuminated recording winding-engine signals in coal mines. (6038) Fleming, J. A. Electric furnaces. (6039) Frangois, A. Filling spaces or cavities difficult of access with concrete, cement, etc. (6126) Ghijsen, H. C. Smelting furnaces with means for inter- mittently cutting off molten mass delivered therefrom. (6057) Hollis, E. P. Controlling alternating current power stations. (6104) Hotchkis, M. H. Forced draught for steam-boiler, etc., furnaces. (6152) Huelin, J. W. Means for preventing or consuming smoke in furnaces. (6202) Imhoff Motor Company Akt.-Ges. Two-stroke-cycle internal-combustion engines. (5981) Marks, E. C. R. (Elektriska Pannrenings Aktiebolaget). Boiler-scale cleaner. (6263) Neilson, L. W. Internal-combustion engines. (6239) O’Sullivan, T. Elevators. (6284) Packard, F. Steam condenser for gas wash boilers. (6275) Patterson, M. J. Means for erection of pit baulks and girders. (6290) Pearson and Son, J., and Smith, J. S. Treatment of coal-tar pitch, etc., for production of fuel. (6280) Phillippo, J. Means to procure motive power. (5944) Preece, T. Drilling or boring apparatus. (6219) Ramen, A. Mechanical roasting furnaces. (6271) Rew, R. J. Retorts for gas production. (6077) Rew, R. J. Retorts. (6313) Richardson. H. Means for working grabs. (5965) Shaw, F. W. Fuel, or combustible or explosive mixture, for motive pawer purposes or explosives. (6006) Simpson, C. W. Heating flues of chambered ovens or retorts for producing gas and coke or fuel. (6230) Smallwood, A. Fire-grates or gas producers. (6228) Smallwood, A. Furnaces. (6229) Spencer, A. Steam superheaters of the multiple smoke or fire tube type. (6208) Stringer, H. T. Internal-combustion engines. (6239) Sutton, C. C. Liouid resistances. (6256) Taylor, J. Internal-combustion engines. (6079) Thompson. A. Furnaces for steam boilers, etc., burning solid fuel. (6012) Thorp, F. and H. T. Refining benzol, etc. (6306) Tuch, C. C. Ebb and tide motor. (6267) White, D. Internal-combustion engines. (6239) Williams, E. O. Hopper wagons. (6250) Williams, G. Producing centrifugal castings in moulds. (6027) Wyld, W. Apparatus for distillation or treatment of ammoniacal liquors, etc. (6122) Ziegler, W. G. Internal-combustion engines. (5988) Complete Specifications Accepted. (To be published on May 2.) [Note.—The number following the application is that which the specification will finally bear.] 1914. 12325. Explosions-Turbine-Studien-Ges. Fuels for'internal combustion engines. 1917. 106. Alchevsky, N. Apparatus for making tunnels. (114443) 3948. Thompson, W. P. (Reilly, P. C.). Process and apparatus for distilling coal tar or the like. (114453) 4785. Scott, W. J. Internal-combustion rotarv engine. (114469) 4873. Dreffein, H. A., and Flinn, M. S. Gas producing and consuming plants. (114474) 4931. Scanes, A. E. L. Steam condensers and the like. (114478) 4935. .Cory, F. G. Screw pumps. (114479) 5027. Cairns, H. S. Fishing tools for use in well boring. (114484) 5037. Macintosh. A. A., and Hunt, W. H. Method of, and means for, equalising or maintaining an equilibrium, or any predetermined condition of pressure in retorts or offtake pipes in the manu- facture of coal gas, or in the volatilisation of . other suitable substances. (105563) 5082, Lassen, J. J., and Hjort, V. F. Apparatus for the softening and purification of water. (114485) 5272. Euler, C. F. : Gas generators. (114491) 5491. Holehouse, W. H., and Holehouse, W. Mechanical stokers for boilers, furnaces, and the like. (114497) 5723. Stewart, A. W. Air injectors or ejectors for use in ventilation. (114499) 5809. Cass, A. T. Grate bars for the furnaces of steam boilers and the like. (114500) 6432. Portham, R. S., and Dornan, J. Superheaters for boilers of the water-tube type. (114508) 6836. Allwright, H. A., and Turner, A. Apparatus for lighting coal fires for domestic purposes with the use of gas. (114514) 6915. Short, A. A., Watkins, W. G., and Fletcher and Company, G. Permanent way stops for con- trolling colliery tubs and .other vehicles. (114515) 7153. Lund, E. K., and Bennett, E. Internal-combustion engines. (114519) 9330. Gill, H. A. (American Steam Conveyor Corpora- tion). Steam jet ash conveyors. (114541) 9920. Grabowsky, R. Hollow water-cooled furnace grates. (107978) 10137. Hamilton, W. L. Aerial or suspended railways. (114548) 10213. Major, C. W. Ventilation and cooling of dynamo- electric machines. (114549) 10229. Howden and Company, J., and Hume, J. H. Fur- nace fronts. (114550) 10810. Campbell, A. F. Conveying and separating or sizing plant, applicable to collieries and other places. (114556) 10844. Jackson, W. J. Mellersh- (Diamond Power ' Specialty Company). Boiler cleaners. (114557) 13382. Howden and Company, J., and Hume, J. H. Fur- naces. (114575) 14403. Howden and Company, J., and Hume, J. II. (114579) 14933. Dixon, J. L. Electric furnaces. (111104) 15700. Lyon, F. Rotary pressure blowers, exhausters, pumps, and the like. (114584) 19019. Boorne, W. H. Wet-carbonising apparatus and process. (114603) Complete Specification Open to Public Inspection Before Acceptance. [Note.—The number following the application is that which the specification will finally bear.] 1918. 2432. Nomi, K. Utilisation of petroleum pitch. (114617) Restoration of Lapsed Patents. An Order has been made restoring the Letters Patent granted to Frederick William Campbell for “ Improve- ments in Concrete and other Piling,” No. 29612 of 1906. William Wilde and William Petrie have made application for the restoration of the Patent for “Improvement in corve retaining and releasing mechanism specially applicable to mine cages and the like,” No. 20245 of 1907, which expire 1 on September 11, 1916, owing to the non-payment of th? prescribed renewal fee. Notice of opposition should be lodged at the Patent Office, on or before June 17, 1918. GOVERNMENT PUBLICATIONS. %* Any of the following publications may be obtained on application at this office at the price named post free. Colonial Reports—Annual : (No. 957) “ British Honduras —Report for 1916 ” (London : Published by His Majesty’s Stationery Office), price l|d. PUBLICATIONS RECEIVED. “Journal of the American Water Works Association” (Vol. 5, No. 1), March 1918 : “ The Journal of State Medicine ” (Vol. 26, No. 4). April 1918 (Published by the Royal Institute of Public Health, 37, Russell-square. London, W.C. 1), price 2s. net; The Institution of Electrical Engineers : “ The Overseas Distribution of Engineering Appliances,” by Leonard Andrews. Member. Distillation of Lignite.—Efforts are being made in France to introduce the distillation of lignite for tars. The Societe de Distillation des Combustibles. Paris, is con- structing an improved Ziegler type of furnace similar to that used for the distillation of peat, a type yielding about 7 per cent, of tar, which is treated by fractional distilla- tions carried out in vacuo, to increase the output of heavy produces; followed by chemical purification by washing with dilute sulphuric acid and soda, to remove the pico- lines, cresols, etc. The crude paraffin, extracted by crystallisation of the heaviest oils, is first passed through the filter-press. The purification consists of a series of filterings in the filter-press, and meltings in light oil. The last traces of oil are removed by scrubbing with super- heated steam, and the paraffin wax is clarified by filtering through animal black. In one place in Germany, where the system was adopted, 70 to 80 per cent, of marketable products were obtained from lignite tar, viz., 15 to 20 per cerit. of paraffin wax; 5 to 20 per cent, of kerosene; 5 to 15 per cent, of creosotes and organic acids; the remainder being light products, petrol, etc., or heavy products, such as gas oils and lubricating oils.