994 THE COLLIERY GUARDIAN. May 26, 1916. mud. In reality, the Carr bit is of the blunt chisel variety, while the H-bit may be called a double-chisel type. However, while the simple chisel-bit may be effective in some rocks with hammer drills, it has definite limitations particularly with piston drills. That the introduction of improved drill bits is a matter of no small consequence, is indicated by the statement by James MaeNaughton, general manager for the Calumet and Hecla Company, that the use of the one-man drill and Carr bit resulted in an increased output per miner equivalent to his total production of a few years ago. Regarding the so-called flat cross-bit—or low-centre cross-bit, which soon wears to the same shape—that is, with edges slightly flattened in proportion to the dis- tance from the centre, it is clear that the additional metal in the wings makes reinforced edges that stand up to the work in hand, giving a stronger and more resistant bit than the ordinary cross-bit, because hold- ing its gauge much longer. The whole idea is to get a bit that will not wear on the edges as quickly as the cross-bit; any method of reinforcing the peripheral edges, while not impairing the cutting speed or impeding the ejection of cuttings, is salutary, and represents the goal as at present recognised. NEW PERMITTED FRENCH SAFETY LAMP. THE KOEHLER “ KO-PAX.” The Koehler “ Ko-Pax ” safety lamp illustrated has been placed on the Permitted List, for use in fiery and dusty mines, by the French Minister of Public Works. The lamp is designed to burn benzine, with a round or flat wick, with bottom feed, double gauze, bonnet, and white phosphorus pellet re-lighter of the Wolf pattern. The air enters the lower part of the lamp through a groove situated between the basal ring and the con- tainer, then traverses a series of grooves in the threaded ring of the latter, and finally enters the interior of the lamp through the openings in the gallery, which are masked by a double brass gauze. The bonnet consists of a cylindrical sleeve, provided over its entire surface, with a series of elongated open- ings arranged, in pairs, in seven rows, 20 in each row. The lower horizontal flange of the bonnet is pierced with circular holes admitting air to the base of the gauze, and the upper part of the bonnet is capped with a horizontal diaphragm which allows the fumes to escape, and is pro- tected from draughts by the crown. The oil vessel and the bonnet are of iron or alu- minium. The gauze is tight- ened against the glass by means of an annular steel spring, which bears, by means of four equidistant points, against the gauze ring and the horizontal flange of the bonnet. The dimensions and shape of the essential elements of the lamp are as follow :— A, Glass.—Cylinder of annealed glass, held between two asbestos washers, the lower of which is inserted into the air inlet gallery, and the upper one in a recess in .the metal fitting. The shape and dimensions are the same as for the Mar- shut lamp. B, Inner Gauze.— Internal diameter at top, 35 mm.; at base, 42 mm.; height, 97 mm. C, Outer Gauze.— Internal diameter at top, 50 mm.; at base, 55 mm.; height, 103 mm. The material of these gauzes is the same as for the Marsaut lamp. D, Bonnet.—Internal diameter, 79 mm.; height, 105 mm. The elongated openings are 4 mm. high and 1mm. wide; and the 10 circular openings are 5 mm. in diameter. The diaphragm at the top of the bonnet must not exceed 58 mm. in diameter, and the distance between the upper orifice of the diaphragm and the outer gauze must not be less than 7 mm. Maximum distance between lamp crown and diaphragm, 12| mm.; -diameter of crown, at least 84 mm. E, Lower Air Inlet. — Circular groove : External diameter, 83 mm.; height, 1| mm. Grooves in threaded ring of oil vessel: Number, 4; width, 13 mm.; height, 2mm. Openings in air inlet gallery: Number, 6; width, 16 mm.; height, 3 mm. The dimensions of the double crown of brass gauze are : Internal diameter, 50mm.; number of meshes per sq.cm., 144; thickness of wire, not less than | mm. The margins of tolerance allowed in the dimensions are the same as for the Wolf lamp with bottom feed. (II)IM) (I j ; 1)1)11 (H) ! UIHHH) ;i 01)11 (JO I'.. OOH (id : ■ 11111(1 (I ; :v Koehler “ Ko-Pax ” Safety Lamp. The German steamer “ Trave,” 762 tons, from Lubeck to Norway with coal, has been torpedoed by a British sub- marine off Kullen, at the northern entrance to the Sound. The crew were allowed to leave in the ship’s boats before she was sunk. MEANS ELECTRIC CAS DETECTOR * The increasing use of self-contained portable electric lamps in coal mines has created a demand for a device other than the ordinary flame safety lamp, for the detec- tion of the presence of inflammable or explosive gases. A detector of the electrical, type has been developed by C. M. Means, of the Randolph-Means Company, Pitts- burg, Pennsylvania, that promises to serve that purpose. It consists essentially of two glowers placed in a vertical position side by side, and enclosed with gauze and glass. The gauze is used to permit the free circu- lation of air or gas, and prevent the communication of flame to the outside in case an ignition should take place inside the enclosure. The glass is used for obser- vation purposes. To this enclosure is-attached a handle, which may contain dry batteries such as are used in an ordinary flash lamp, or it may only contain the cord connections in case a storage cell is used. The battery which furnishes energy to operate a cap lamp may be used to supply electric current to the glowers by attaching an additional cord, and the energy used for the. detector will not appreciably shorten the time the lamp burns, for only a small amount of current Fig. 1. Seams on the Ekaterininsk and Edwardovsk properties. o eg g r. in tn z z c3 ® . 7 = g 2 d 02 - '5 < 44 ’2 ® £ a 2 | tn 44 tn O § s - tn 44 tn O - 0) 3 2 3 02 w. z 3 s ra DO O fl 75 .n « — t> t» H is required to energise the detector. The device can be made rugged, and of such size as will allow of its being easily carried in the pocket. One Glower Brightens and the Other Dulls. To use the detector it is necessary to press a button, which energises the two glowers, heating both to a dull red. In air containing no inflammable gas, both glowers will be of exactly the same colour, but in methane or other inflammable gases one of .the glowers will increase in temperature, with a corresponding increase in luminosity, while the other glower will decrease in temperature, and give accordingly a reduced emission of light. The relative difference in tempera- Ashaninsk Mine, pit No. 7, south bottom gallery < 23° Alexeievsk Ashaninsk Mine, shaft No. 2: 1st section in 1 st seam. Seam 1 Ekateri- ninsk W < 3 - 5°. seam. Ashaninsk Mine, Alexandra shaft: Alexandrovsk seam, depth 15 sazhens (15 sazhens = 105 ft.) south gallery 50T10 <32°. Fig. 3. ture and luminosity indicates the percentage of inflam- mable gas present. It is claimed that this device can be constructed to indicate the presence of 0-5 pex- cent, of methane, but the most practicable device is intended to clearly indi- cate the presence of 2 per cent, or more of gas. It can be so operated that no ignition will occur inside, the enclosure, no matter what the percentage of gas may be, as the temperature of the glowers can be kept sufficiently low so that the glow will not ignite the methane, even when mixed in ignitable proportions. A sufficiently high temperature will be reached, however, by larger percentages, but that is unimportant, for when the glower by reason of the greater percentage of methane * Goal Age. becomes hot enough to ignite the mixture, the latter will be too full of methane to sustain combustion. No attempt is made in this device to record accurately the percentage of gas present, • but to indicate only whether explosive gas has been encountered in dan- gerous quantities. With care the percentage can be closely approximated. CHELIABINSK (URAL) BROWN COAL MEASURES.* By A. Snyatkoff. The Cheliabinsk coal deposits, which contain brown coal seams, have been known since 1832, 'when they were discovered by the mining engineer Redikortzieff on the River Miass, near the village of Ilyinsk. But it was only in 1906, with the discovery of similar deposits near the village of Tugai-Kul, about 4 versts south of the Siberian Railway, that interest in the district was re-awakened. The deposits were found to include many workable seams, and in the year 1907 the Ekaterininsk Mine of the Ashanin Company was opened, which still supplies a large part of the coal produced in the Chelia- binsk region. The Cheliabinsk Company’s mine lies southward of this Ekaterininsk concession, and the Serginsk-Uphaleisk Factories’ concession comes next. North of the Ekaterininsk Mine, nearer the railway, Fig. 2. Syncline in the Serg-insk-Uphaleisk property. 0-03 0-15 0-02 0-01 0-09 Ashaninsk Mine: Alexeievsk seam, between pits Nos. 2 and 7. Depth 7'5 sazhens (521 ft.) < 13°. 0T2 0-02 0'12 0-02 0’03 0'07 0'01 0'01 0'05 Ashaninsk Mine, shaft No. 2, Seam II, Ekateri- ninsk. is the site of the Kyshtim Works. Several other con- cessions have ,also been granted. The coal measures consist of schisty clay, sandstone, and conglomerate, with spherosiderite and siliceous lignine agglomerations. There are numerous seams of brown coal, 0-30 to 3 sazhens (1 sazhen = 7 ft.) thick. The total number of seams in the series, and their exact constitution, however, is not yet known-. The total thickness is well over 100 sazhens (700 ft.), and the number of workable seams is at least 10. The coal deposits lie in a series of folds running almost due south, and conforming to the general direc- tion of the Ural dislocation. These folds are compli- * From the Journal of the Imperial Russian Technical Society.