590 THE COLLIERY GUARDIAN. March 13, 1914.. '»S 14637 (1913). Improvements in Rock Drills. G. Meyer, of Altenkessel, Saarbrucken, Germany.—Relates to percussive rock drills of the type in which a series of outwardly projecting teeth with radial cutting edges are arranged upon the free end of a drill shank around a removable central bit. Fig. 1 is an elevation, and fig. 2 a plan of the improved drill with four cutting edges; fig. 4 is an elevation of a central bit, fig. 5 a plan of a drill with five cutters, fig. 6 a longitudinal section through a drill with a modified central bit, and fig. 7 a plan of the same. On the free end of a shank B adapted to be secured to the shaft of a drilling machine there are formed a plurality of outwardly pro- jecting teeth constituting radial cutting edges A. The roots of the teeth do not meet at their inner edges, but leave a central flat base b between them. In the cavity formed between the teeth there is arranged upon the flat base b of the shank the central bit C. This bit may have the shape of a truncated cone c with a sharpened point c1, which preferably 1 III does not reach the hoiizontal plane of the cutting edges. The central bit is secured in position by means of a slightly tapered stem c2 fitting into a recess in the drill shank. The stem is of smaller diameter than the central bit, so that a shoulder c3 is formed between them which rests upon the metal forming the base and surrounding the recess in the shank. The central bit is thus rendered incapable of axial displacement, and has not the tendency to burst the drill shank or to become so tightly jammed in place that its removal offers great difficulties. The force of the blows is taken up by the shoulder. The central bit may have any suitable shape, according to the work for which the drill is intended, as long as there is a shoulder between the head and the stem. It may, for instance, be provided with radial cutting edges similar to the drill itself. Such a bit is shown in figs. 6 and 7, c4 being the cutters which are preferably placed between the cutting edges of the drill. The number of cutters arranged around the removable central bit may vary from three to seven. (Three claims.) 16265 (1913). Improvements in Hoods or Head-coverings for use in Impure Atmospheres. 1’. J. Garrity, of 1842, McKean-street, Philadelphia, Pennsylvania, U.S.A,—Relates to hoods or head-coverings for use in impure atmospheres, and is of the type in which a metal helmet is provided, having a jacket or apron of leather or the like, depending from its lower edge and supplied through flexible pipes with compressed air. The primary object consists in providing a hood with a flexible apron open around its lower edge to 16 .a 5 -jg allow for the escape of the impure air which is forced out by the incoming charge of fresh air under pressure, and thus does not cause undue pressure to be exerted on the lungs of the workman. A further object is to provide an improved construction. Fig. 1 illustrates the improved device in operative position; fig. 2 is a view in longitudinal section ; fig. 3 is an enlarged sectional view illustrating the air inlet to the helmet. (Six claims.) , 1 17011 (1913). Improvements in Apparatus for Washing Coal and other Minerals. P. Habets, of Montegnee, Belgium, and A. France, of rue de FEsperance, 233, Liege, Belgium.— Relates to improvements in washing apparatus for separating substances of different specific gravities, and particularly to apparatus of the kind in which the material to be washed is fed into a hopper or trough, and is carried down by a stream of water which passes below an adjustable partition arranged above the mouth of a discharge passage through which an ascending stream of water passes, the particles in the material which are of sufficient density to resist the ascending stream falling down the discharge passage, while the dust or other material of less density is carried away up the other side of the partition and over the side of the hopper or trough. The object of the present invention is to enable the velocities of the streams on both sides of the partition to be very accurately regulated so as to suit the material which is to be deposited or separated out, and to permit of this regulation being effected without interference with the velocity of the ascending stream in the discharge passage in the bottom of the trough, the velocity of which stream it is desirable to control as usual by independent means. With this object in view, the invention consists in arranging the adjustable partition or shutter, above the discharge passage, and in such relation to the sides of the trough that, when the said shutter is raised and lowered the cross-sectional areas of the streams passing between it and the sides of the trough are varied simultaneously—that is to say, if the shutter be moved to vary the cross-section, and consequently the velocity of the downward entraining stream on one side of it, it will also effect a corresponding variation in the cross-section and velocity of the ascending stream on the other side of it, in spite of the fact that this ascending stream will receive a certain velocity due to the stream which ascends in the discharge passage at the bottom of the trough. Another object of the invention is to enable the ascending stream on this side of the trough to be so regulated as to ensure that the particles which other- wise remain in suspension shall be deposited on the inclined wall of the trough, and shall descend the same and enter the discharge passage at the bottom thereof. This object Fry. 4. is attained by providing an adjustable shutter at the point of discharge or overflow, so that the depth of the over- flowing stream can be accurately regulated as and when required. The invention further comprises the provision of a hinged flap on the central shutter or partition, so that a finer adjustment can be made after an initial or compara- tively rough adjustment has been effected by sliding the central shutter itself. In applying the invention to a trough having a plurality of passages through which ascending streams pass, a plurality of flaps are used and arranged in a special manner. A hinged flap, moreover, may be fitted to the inclined shutter at the overflow of the trough. Figs. 1 and 2 are diagrammatic views showing in sectional elevation and plan one form of apparatus according to the invention; fig. 3 is a diagrammatic sectional elevation showing a similar form of apparatus to that shown in fig. 1, in which the shutters are provided with hinged flaps; fig. 4 is a diagrammatic view illustrating in sectional elevation and plan a form of apparatus in which a plurality of flaps is used and arranged above a plurality of passages for ascending streams; fig. 6 is a detail side view of the shutter shown in fig. 4. (Seven claims.) 20668 (1913). An Improved Process for Producing Peat Fuel or Coke, and Apparatus therefor. W. L. Sc. J. Prioleau, Pen-y-Lan, Boncath, South Wales, and J. R. H. Pxioleau, 1, Trafalgar-square, Chelsea, London.—Relates to improve- ments in the method of producing peat fuel either for use as fuel, or for further treatment in order to produce peat coke, and to apparatus used in carrying out the method in practice. It has been found that to prevent vapourisation and loss of the volatile oils, the temperature must not rise beyond about 30 degs. Cent, during the production of the peat fuel, and the invention consists in a method of obtaining blocks of hard condensed peat by first thoroughly com- minuting the raw peat, as taken from the bog, then raising the temperature of the mass, in a steam-jacketed space under accurate control, to about 30 degs. Cent., immediately tit nwk moulding it while still wet into lumps, or soft blocks, under slight pressure only, and finally submitting the said blocks to a drying action over several days in sheds heated so that the peat reaches, initially at any rate, a temperature of about 30 degs. Cent, only, and never rises much above that temperature. The first application of heat is solely for the purpose of rendering the viscous constituents of the peat sufficiently sticky to cause the binding of the mass into blocks during the moulding process, without the addition of extraneous binding materials. By using only surface heating a certain amount of drying is, however, effected at the same time, say perhaps a reduction of the water contents from 90 per cent, to about 70 per cent, which is advan- tageous, and the later heating is for slowly removing the* moisture from the blocks, especially from the centre of the blocks, and at the same time causing their condensation, and solidification. The solidification is the important step, and is attained by reason of the blocks being only of such a. consistency (approximately that of putty) obtained by moulding wet, that when subjected to the drying the air-current will penetrate to their inmost recesses and remove the moisture therefrom. To accomplish this it is necessary that the outside of the blocks are dried slowly,, and this is attained by keeping the air-current moist owing to the blocks still containing most of the peat water when first submitted to the drying action, by reason of which the air-current constantly carries with it moisture from the drying blocks; the air-current, which would otherwise become dry eventually, receives accessions of moisture from each new batch of blocks which are brought to the drying sheds. Fig. 1 is a general view showing a plant for carrying the invention into effect; fig. 2 is a transverse view, partly in section, on the line a, b, of fig. 1. (Six claims.) 22476 (1913). Improvements in and relating to Mills for Grinding, Crushing, and Pulverising Ores and the like. E. S. King, 37, Walbrook, London, and Head, Wrightson and Co. Limited, Teesdale Ironworks, Thornaby-on-Tees, Yorkshire. —Relates to methods of and means for grinding, crushing, and pulverising ores and the like by means of pan mills of the disc type, and it has for its objects the prevention of unnecessary sliming, the removal of the concentrates periodically during the running of the mill, the removal of the accumulation of heavy mineral particles such as iron from the shoes and dies which gather in the pans of these machines, and generally to increase the efficiency of the treatment of ores by pan mills of the type specified. These ends are obtained by providing means whereby the accumu- lation of concentrates in the pan can be intermittently discharged at such intervals as practice may decide, having regard to the ore under treatment, and whereby said discharge is rapidly and efficiently effected without drawing off any of the slime. The whole of the material is left in the pan until it is slimed and overflows at the top of the pan, the result of which is that the valuable mineral being of the greater specific gravity is brought into closer contact with the crushing surfaces, and by reason of excessive grinding is reduced to such a small size that a large portion, is subsequently lost. Consequently by withdrawing this concentrate from the grinding mill the recovery from the treatment plant must of necessity be improved. As the concentration of mineral which takes place within the pan is found to have a value directly in proportion to the period of operation of the pan on any given value of feed, the rich concentrate can be withdrawn by discharging the pan periodically. A mill for carrying out this process comprises a pan fitted with the usual disc dies and shoes, suitable driving apparatus, baffle plates, and a “ spitzkasten33 or circumferential overflow, and in the bottom of the pan below the grinding zone is a suitable outlet provided with a suitable valve or shutter whereby same can be opened and closed as desired. Fig. 1 is a view in elevation, partly in section; fig. 3 is a view in section of one of the valves.. (Five claims.) REW PATENTS CORRECTED WITH THE COAL ARD IROR TRADES. Applications for Patents. 5262. Rope and cable grips for underground haulage and the like purposes. G. Beecroft. 5267. Weighing machines. Henry Pooley and Son Limited,, and J. Dobson. 5300. Drilled cores. Nederlandsche Maatschappij tot het verrichten van Mijnbouwkundige Werken. 5301. Apparatus for cutting off the tubes used for lining boreholes. Nederlandsche Maatschappij tot het verrichten van Mijnbouwkundige Werken. 5302. Bits for hollow drills, i e., core drills. Nederlandsche Maatschappij tot het verrichten van Mijnbouw- kundige Werken. 5303. Catch devices for boring-rods. Nederlandsche Maat- schappij tot het verrichten van Mijnbouwkundige Werken. 5304. Grippers for use in connection with boring operations.. J. Koster and Nederlandsche Maatschappij tot het verrichten van Mijnbouwkundige Werken. 5305. Boring plants. J. Koster and Nederlandsche Maat- schappij tot het verrichten van Mijnbouwkundige Werken. 5306. Construction of pump, motor, or like apparatus. R. F. Carey. 5316. Process for the reduction of metals from their ores. J. M. Skelley. 5367. Fluid-pressure engine compressor or the like. S. H. Berry and E. A. Mills. 5380. Electric re-lighting apparatus for safety lamps, as used in mines. J. J. Pugh. {Continued on page 592.)