July 16, 1915. THE COLLIERY GUARDIAN. 135 sifting the material being ground during its passage from the preliminary mill into the fine grinding mill. By this means, without the use of sieves, the material issuing from the preliminary mill is separated into two parts, of which one part is conveyed for treatment into the fine mill, whilst the other part is returned into the preliminary mill. The material under treatment is conveyed to the fine mill directly to the points corresponding to the degrees of fine- ness of such material, so as to prevent useless grinding. Then after the jet or current of air has effected the separa- tion between the preliminary mill and the fine mill, it is caused in entering the fine mill to assume an injector-like action, so that the fine material is drawn from the casing surrounding the preliminary mill, and is conveyed into the fine mill. The material treated in the preliminary mill is fed to the air jet or current preferably by a wheel-shaped hopper device of known construction, located in a chamber between the preliminary mill and the fine mill. Fig. 1 is a longitudinal axial section of a form of apparatus com- bining a preliminary mill and a fine mill in one and the same machine; fig. 2 is a separate view of the feeding device. (Five claims.) 6767 (1914). Improved Means for Use in the Quantita- tive Analysis of Gaseous Mixtures. Siemens Brothers and Company Limited, of Caxton House, Westminster, London. (Communicated from abroad by Siemens und Halske Akt.- Ges., Nonnendamm-bei-Berlin, Germany.)—The invention is a modification of the arrangements shown in Letters Patent No. 28943 of 1912, and forms an addition thereto. It has been proposed to determine the density of a gas by measuring the difference of pressure between two points, one near the axis, and the other near the circumference of a centrifugal blower, or the like, through which the gas is passed. It has also been proposed to compare the density of a gas with that of a standard gas under similar condi- tions by comparison of the readings of the two instru- ments. According to the present invention, the relative densities of the mixture and of the standard gas, and hence the proportion in which the constituents are present in the mixture, is directly given by the indications of a single instrument, but this instrument is only exposed to the pressure differences produced in the gaseous mixture? the pressure differences produced in the standard gas being 22' 12 7 ^2 I 19 automatically maintained at a constant value, independent of changes of temperature and pressure. If the gaseous mixture is always exposed to the same conditions as the standard gas, the readings of the instrument which records the pressure differences set up at two different parts of the rotating gaseous mixture will also be independent of changes of temperature and pressure, and the proportions of the constituents of the mixture will consequently be directly shown on a single scale. In order to maintain a constant pressure difference in the standard gas, its indicating device moves between two electrical contacts only a small distance apart, so arranged that when one contact is closed by means of the indicator, the speed of the motor driving the centri- fugal blower is increased, and when the other contact is closed, the speed is decreased. In this way a constant pressure difference is maintained at the manometer of the standard gas, and if care is taken that the other centrifugal blower rotating on the same shaft has the same pressure and temperature as the standard gas, the manometer connected to it will give indications which show directly the proportion present of a given constituent of the gaseous mixture. An arrangement according to the invention is shown diagram- matically in the accompanying drawing. (Three claims.) 17732 (1913). Process for Converting Coke into Graphite. H. Plauson, of 23, Pessotschnaja, St. Petersburg, Russia.— In accordance with the invention, coke can be converted directly into the condition resembling colloidal graphite, and this graphite can be obtained directly in oil. It has been found that when coke, finely disintegrated mechani- cally (coke powder), is converted into colloidal solution in any known manner, or as described with reference to coal in co-pending applications Nos. 17729/13 and 17731/13, graphite is obtained. As, however, as indicated in these patents, the colloidal or emulsion-like condition of the carbon can also be brought about in liquid hydrocarbons, it is possible to obtain a colloidal solution of graphite in oil directly from coke powder. When necessary the finely- divided graphite can be separated in any known manner from the liquid, and brought to any other desired form. In this case it is advantageous to use water or some thin liquid hydrocarbon, such as kerosene or ligroin, for example, instead of oil. If it be desired to obtain chemically pure graphite, the coke powder is purified by the acids specified in the specification of co-pehding application 17731 of 1913, which are then neutralised with lyes, whereupon washing with water is effected. If, in order to improve the plasticity, clay or the like is added to the graphite, this clay or the like can be mixed in the form of powder with the coke powder, and clay is obtained in the colloidal condition as well as coke. It is also very advantageous either during or prior to the conversion of the coke powder into the colloidal form to add to the mixture from 1 to 3 per cent, of some natural colloid, or in lieu thereof, aldehydes, tannin or tungstic or chromic acid and the like, because by this means the decom- position of the particles of coke is facilitated. (Two claims.) 20254 (1913). Improvements in Safety Devices for Mine Gages. E. Tillack, of 54, Gerichtstrasse, Berlin, N., Germany.—For arresting mine cages upon breaking of the rope, it has been proposed to use toothed jaws, which are pressed against the guides and thus adapted to stop the mine cage. In the event of the guides yielding to the pressure of the toothed jaws, lateral projections are provided on the jaws, which embrace the guides until they abut against the pit timbering. According to the invention, the contact jaws are constructed as braking jaws, for which at normal load the distance that the unsupported cage would travel with the brakes on can be previously determined, while besides, independently of the action of the jaws, locking bolts are provided, which at the moment of the breaking of the rope, or at an exceedingly high speed of the \----4' XT ~~ f 30 M cage, are projected and placed upon spring buffers arranged at the height of each level. Thus, upon breaking of a rope happening shortly before the cage reaches the height of a level, the bolts are already able, by placing themselves upon the spring buffers, to stop the cage and to weaken the shock. If, however, for any reason, the distance that the unsupported cage would travel with the brakes on is too short, the braking jaws can be slightly loosened by a hand- or foot-operated mechanism, in order to permit of the cage sliding further downwards to the height of a level, where it is finally stopped by the locking bolts. Fig. 1 is a sectional front elevation of the cage during its normal operation; fig. 2 is a similar view of the same, after breaking of the rope ; fig. 3 is a horizontal section on the line A—B of fig. 2 ; fig. 4 is a vertical section on the line C—D of fig. 2, through the parts effecting the movement of the bolts in two different positions; fig. 5 is a side view of the braking device. (Two claims.) 20496 (1913). Improved Apparatus for the Manufacture of Blasting Cartridges. Dr. S. Laszczynski, of Miedzianka, near Kielce, Russian Poland.—Relates to an improved apparatus for the manufacture of cartridges according to the “ Sprengel ” system. In the production of explosive sub- stances, according to the “ Sprengel ” system, dry cartridges of alkali chlorates are impregnated with liquid fuel, especi- ally kerosene. In lieu of alkali chlorates, other oxygeni- ferous substances, for instance, perchlorates and nitrates, can, of course, be used for this purpose. The invention relates to an apparatus by which a homogeneous and thorough impregnation of chlorate cartridges is obtained automatically under quite unvariable conditions, and inde- pendently of the intelligence and the skill of the workman. The dry cartridge, enveloped in perforated paper, is placed into the opened automatic apparatus, which is then closed by the single movement of a controlling lever, and the cartridge tightly enclosed on all sides. Simultaneously, a measured quantity of liquid fuel is discharged homo- geneously over the whole surface of the perforated cartridge. After saturation of the cartridge with the liquid fuel, the apparatus is opened by moving the lever in the opposite direction; by the same movement of the said lever a fresh quantity of liquid is measured off for the next impregna- tion, and the impregnated cartridge is then removed in a condition ready for use. In order to obtain a perfectly homogeneous discharge of the total quantity of liquid fuel necessary for the saturation of a single cartridge, the fuel must be divided into a large number of separate portions. Fig. 1 shows a measuring receptacle constructed according to this principle (the apparatus itself consists of a large number of such receptacles). The conical valve a has a hole b drilled to about two-thirds of its diameter, the hole b constituting the liquid receptacle. In fig. 1 the hole b is shown in communication with the kerosene receptacle p above. The air holes c and c1 are closed when the valve is in this position. By turning the valve about 180 degs. (fig. 2) the air holes c and c* register and the liquid flows downwards from 5, air entering at the same time by the air orifices c, c1 and replacing the liquid. A single cartridge weighing 400 grammes (or four cartridges of 100 grammes each) requires 'about 100 such small receptacles for effecting thorough saturation. The simultaneous rotation of all the receptacles through an angle of 180 degs. is performed by mounting the valves on a few common axes, which are connected together by means of toothed gears; thus, by rotating one axis with a crank, all the others are rotated simultaneously to the same angle. (Four claims.) NEW PATENTS CONNECTED WITH THE COAL AND IRON TRADES. Applications for Patents. 9743. Steam exhaust nozzles. F. Mertscheimer. 9757. Rotary blowers. J. Keith and G. Keith. 9763. Fuel piping arrangements for coke ovens. A. Roberts. 9764. Foundations for coke ovens. A. Roberts. 9765. Expansion control devices for coke ovens and the like. A. Roberts. 9771. Means for inducing respiration and like purposes. W. J. H. King. 9777. Signalling apparatus for use in collieries and other mines. J. Holland and W. H. Becker. 9780. Purification of distillation gases of coal. E. Ciselet and C. Deguide. 9787. Process of manufacturing rings and tyres of iron or steel Deutsch-Luxemburgische Bergwerks- und Hiitten-Akt.-Ges. 9791. Machine for rolling flanges. G. Harrison. (Stan- dard Welding Company, U.S.A.) 9797. Apparatus for opening and closing electrical circuits at a certain temperature. E. J. Sumner. 9816. Rotary blowers, pumps, or the like. H. R. Ricardo. 9834. Electric mine lamp. J. W. Rigby. 9838. Manufacture of bituminous substances. C. Richard- son. 9847. Steam condensing apparatus. A. E. L. Scanes. 9891. Pneumatic elevators and conveyors. H. J. H. King. 9895. Railway wagon and like coupling gear. G. Gillies. 9896. Construction of wheels. C. Chailiner. 9901. Centrifugal compressors. British Thomson-Houston Company Limited, and R. H. Collingham. 9917. Pumps. W. H. Mort. 9932. Apparatus for mechanically moving or handling material in bulk. A. Holland and E. R. Royston. 9952. Manufacture of chromium and iron compounds. T. J. I. Craig, and Peter Spence and Sons Limited. 9962. Process of manufacture of picric acid. L. G. Badier. 9990. Core making machines for foundry purposes. J. J. Warren and W. Valentine. 9992. Furnaces. W. Bache. 9998. Metallic packing. A. Bowie and W. Samples. 10016. Reversing gear for transporters, friction hoists, and the like. P. Preston. 10017. Apparatus for use in giving visual signals. R. M. Abraham. 10022. Extraction and recovery of vaporous constituents from coal gas. R. Lessing. 10030. Shaft and axle bearings. A. Carlborg and G. Nyman. 10033. Ball mills. F. E. Marcy. 10046. Steam ejectors arranged in series with intermediate condensers. Contraflo Condenser and Kinetic Air Pump Company Limited, and C. F. Higgins. 10056. Water tube boilers. H. A. Turnbull. 10058. Means for discharging retorts. Gibbons Brothers Limited, and E. Masters. 10059. Vibrating make-and-break devices for use in electric signalling. A. C. Brown. 10066. Purification of benzol. G. L. Moss and Simon-Carves By-Product Coke Oven Construction and Working Company Limited. 10075. Apparatus for preventing overwinding and/or over- speeding in connection with mine cages, elevators, and the like. J. Devey. 10076. Means of obtaining the weight of railway rails, girders, beams, or similar sectional lengths. Henry Pooley and Son Limited, and J. Dobson. 10081. Haulage clips. W. Sylvester. 10101. Method of casting ingots, and particularly steel ingots. T. D. Kennedy. 10103. Haulage clip. G. J. Coles. Complete Specifications Accepted. (To be published July 29.) 1913. 19822. Transmission of heat to the water in steam boilers. Hulsmeyer. 25955. Turbines and other like machines. Kaplan. 26137. Metallic pipes and tubes. White. (Geb. Jacob.) 26247. Chain grates. Thomke. 26461. Regulating devices for piston steam engines working without a flywheel and having steam-actuated dis- tributing means. Nagel. 26652. Chain conveyors. Schmidt. 1914. 3130. Apparatus for marking out angle iron. Walde. Kade and Erath (firm of). 4243. Method of treating the gas liquor in small gas works. Berlin-Anhaltische Maschinenbau Akt.-Ges. 4355. Device for the storage of heat. Allgemeine Elektri- citats-Ges. 4539. Means for removing the sintered together burnt material, for instance, cement from kilns, or the like, with horizontal kiln chambers. Lorenz. 4574. Manufacture of light hydrocarbons from heavy hydrocarbons. Bergius. 4643. Tube rolling mnls. Mannesmannrohren-Werke. 8305. Signalling system for use in mines and the like. Smith. 8939. Appliances for supplying oxygen or air to divers and others. Mellersh-Jackson. (Dragerwerk, Heinr. und Bernh. Drager.) 9037. Apparatus for transporting metals and other materials. Thoss. 9154. Apparatus for supplying air to furnaces, especially to gas generators. Poetter Ges. 10071. Apparatus for the destructive distillation of sewage sludge. Niibling and Krauss. 10086. Water jet condensers. Geb. Korting Akt.-Ges. 10114. Axial reaction or screw pumps. Vogel. 10157. Water purifying apparatus. Maschinenbau-Anstalt Humboldt (firm of). 12833. Hollow railway sleeper made of reinforced concrete. Michael.