May 53, 1913. THE COLLIERY GUARDIAN. 1083 less. The half-bushings or pads may be retained in position in the axle-box and prevented from moving longitudinally of the axle by suitable means. The axle-box may be con- structed with projecting parts or recesses in which the ordinary straps may be placed for fixing the box to the underframe or carriage of the truck; or the axle-box may be fixed to the truik by any other preferred means. Fig. 2 is an elevation of the axle-box detached and drawn to an 32 6 25, 6 30 C$2 — Lz^ // ^<22 * 30 29 3i =tei 9 3< i 32 JQ6 £g,7 enlarged scale ; fig. 3 is an end elevation of fig. 2 ; fig. 4 is a longitudinal sectional elevation of the box detached and drawn to an enlarged scale with a portion of the axle in position therein ; fig. 5 is a cross-section of fig. 4 on line x—x ; and fig. 6 is an end elevation of one of the half- bushings or pads detached ; and fig. 7 is a side elevation of said half-bushing or pad. (Six claims.) 9066 (1912). Improvements in or connected with the Weighing Mechanism of Weighing Machines. L. Jacob, of John Bright-street, Birmingham, Warwickshire, and Henry Pooley and Son Limited, of John Bright-street, Birming- ham, aforesaid.—Has reference more particularly to that type of weighbridge or weighbridge mechanism in which there are employed a plurality of automatic weight- indicating mechanisms in the form of movable arms or levers, having on them resistance weights, and different weights, or being differently weighted; all being connected up with, and interconnected with the main weighing levers of the weighing machine or weighbridge, and also with one another, through a plurality of whiffletree type of inter- connecting levers; they being so arranged and adapted by their connections and interconnections that the different arms or levers and weight-indicating means come into action or use with loads of different weights. According to this invention, mechanism of the kind referred to is pro- vided, not only with a plurality of scales on the quadrantal weight scale dials, which are of the major order of weight— say tons, cwts., and quarters, but also with a plurality of scales of the minor order of weights—say pounds, on the edges of a plurality of windows through which the major order of weights is seen; diagonal or equivalent lines on the quadrantal dials, extending across the face from the major weight numerals, and working in connection with the minor or pounds stationary scales on the windows. The scale lines in the quadrantal dials may be diagonal or oblique, and the window scales horizontal; or the scale lines of the quadrantal dials may be horizontal, and the window scales diagonal or oblique. Per se, this kind of com- bined weight scales is known, and is not in itself claimed as novel hereunder. Usually, in weighing, the weigher will know which weighing indicating mechanism will come into action prior to weighing a load ; and all the others may be stopped off or relieved by a relieving or stopping off means, so that if desired only the one which corresponds with, or is adapted to take the load to be weighed, will be free and in action. Fig. 1 is a side elevation of it, and fig. 2 a back end view, while fig. 3 is a front end view showing the weight-reading windows. (Three claims.) 9624 (1912). Improvements relating to Portable Respiratory Apparatus. J. Harger, of Grange Hollies, Gateacre, near Liverpool.—The object is to provide means for testing the air, for indicating the percentage of oxygen in it, or indi- cating when the air contains a too large percentage of nitrogen or of carbon monoxide gas to make it safe or desirable for breathing. The apparatus may also be designed to absorb the carbonic oxide gas to some extent. A flame is placed in the intake air of the respirator. By using a very small flame the content of oxygen is not seriously decreased, and by using an intermittently lighted flame this factor can be eliminated almost entirely. The ordinary miner’s lamp will not burn in air which is quite fit for respiration, so that a less sensitive indicator, such as acetylene, or even benzine, is advisable. For instance, if a small acetylene gas flame be used, it will burn in air containing as little as 9| per cent, of oxygen, but it begins to lose luminosity at about 12 per cent., and gives very little light at 11 i percent* of oxygen, which is the point at which air becomes dangerous for breathing. Benzine will go out or will not light when the percentage of oxygen falls below 16| or thereabouts. Such an intermittent device may be operated by clockwork to produce a flame every minute or there- abouts. To ensure that the flame gives a true indication of the percentage of oxygen, the air is passed over calcium 26"'^?* 22 24 2. . te b- s23 27 chloride to absorb any moisture present in the air before it reaches the indicator flame. This also has the advantage that the resulting air is better for breathing purposes. For the purpose of indicating the presence of carbonic oxide gas (CO) or for absorbing it, the air may be caused to pass over or through a vessel containing some fresh blood. A colour scale may be arranged beside the vessel containing the blood. Blood may be used in this apparatus in a concen- trated form or in a form after treatment, so as to concentrate and preserve from decay the haemoglobin. The blood or the concentrated product may be distributed over wood wool or the like, in order to expose a large surface, and it may be contained in a transparent tube or in a tube with view holes formed in it, so that the colour can be observed and the progress of the using up of the haemoglobin can be readily seen. Fig. 1 is a side view of a respirator provided with a continuously-burning indicator flame; fig. 2 is an end view of the same; fig. 3 is a side view of a respirator provided with an intermittently-lighted flame device; fig. 4 is a side view of another form of indicating device and respirator ; and fig; 5 is an end view of the apparatus shown in fig. 4 (Four claims.) 25835 (1912). Improvements in or Connected with Supporting Frames for Apparatus for Boring Holes in Mines. E. Meyer, of Remscheid, Germany.—Relates to supporting frames for apparatus for boring ventilating holes overhead in mines from a lower tunnel or gallery into an upper ventilated tunnel or gallery, and comprises a frame carrying a movable crosshead with means for raising the latter according to previous arrangements, while it further comprises a com- pressed-air tube, which carries a rock drill fitted with a suitable tool and driven by the compressed air, is carried on the movable crosshead and raised in order to feed the rock drill which is slidingly mounted in the upper stationary crosshead of the frame. The accompanying drawings show a front elevation of the apparatus. (One claim.) 26681 (1912). Device for Automatically Stopping Electric Hoists. The British Thomson-Houston Company Limited, 83, Cannon-street, London, E.C. (a communication from the Allgemeine Elektricitats-Gesellschaft, of Friedrich Karl- Ufer, 2-4, Berlin N.W., Germany).—The controlling circuit fed by a generator mechanically connected to the hoist motor contains a variable resistance controlled by the depth indicator or a similar device so that no special apparatus is required for exciting the field of the generator. The controlling circuit is preferably not closed until the commencement of the slowing-down period, so that unneces- sary loss of energy is prevented and auxiliary contacts mny be provided to ensure the operation of the safety device when men are being carried instead of ore. Fig. 1 shows a constructional form of the invention, and fig. 2 shows & diagram. On the voltage falling below a certain value, the solenoid 3 releases its iron core so that the catch 5 which holds the switch 2 in the “ on ” position is released and is caused to break the circuit by any suitable means, such for example as a spring or weight. The circuit containing the solenoid 3 is controlled by an electro-magnetic switch 6. The coil of this switch 6 is in the controlling circuit, so that the switch 6 and switch 2 are opened simultaneously when the current in the said controlling circuit rises above a certain value. The controlling circuit 8 is fed by means of a small generator 9, which is driven from the hoist motor or hoist drum, so that the potential developed by this generator varies with the hoisting speed. The generator 9- can be a three-phase motor with a single-phase rotor, or with a rotor of which only one phase is used. The stator of this generator is excited from the mains in such manner that it produces a rotating magnetic field. The rotor is driven in the above manner at a high speed in the opposite direction to the rotating field. The potential e (fig. 2), which varies with the hoisting speed, can be taken at the two slip rings. When the rotor is stationary this potential has the value Es, and is induced in the stationary rotor by means of the rotating field of the generator 9. When the hoist is in motion, this potential is increased by the component En, which is dependent on the speed of the rotor and is proportional to the hoisting speed. In series with the controlling circuit is a resistance 11, the operating arm of which is moved by means of the hoisting cage, or by the depth indicator or a similar apparatus. This resistance 11 is operated in such manner that the total impedance of the controlling circuit is decreased during the period of slowing down. The curve of the potential and total impedance during the normal slowing down is shown in fig. 2 by means of an inclined full line. Should the hoist be retarded more slowly than under normal conditions, then the E M.F^ would decrease more slowly than the impedance, and would be represented during the slowing down by the undulated dotted line in fig. 2. In this case the current in the controlling circuit would not remain approximately constant as on slowing down under normal conditions, but would rise to a higher value, and therefore operate the switch 6, thus opening the main switch 2. If necessary, an arrangement mJ /9 could be provided which would not only cut out the hoist motor, but would aho apply the brakes. In order to prevent unnecessary loss of energy in the controlling circuit 8, it would be of advantage not to close the circuit until the cage or skip arrives at a point in the shaft at which the above apparatus should begin to operate. For example, this can be carried into effect by providing in series with the controlling circuit two contact bars 17 which should be short-circuited by means of the contacts on the arm 18 carried by the rod 12, when the cage or skip comes to the point at which the control of the slowing down should begin. The arrangement may not only be used when the slowing down is controlled by hand, but can also be applied when it is controlled automatically such as by means of a depth indicator or similar apparatus. In the case of balanced hoisting, this arrangement can be installed in such a manner that when the second cage or skip approaches the mouth and the first cage the bottom of the shaft, a second rod 121 is so provided that it rises at the same time as the aforesaid second cage or skip and operates the arm of the resistance 11 by means of a second pinion 161, which is rotated by means of its rack 141 and a corresponding collar 131 provided on the rod 12>. This rod 121 also carries contacts 181 for short-circuiting the bars 171 which are connected in parallel with the bars 17, and in series in the controlling circuit 8. By means of a second pinion operated by the rod 12 or by a second rod connected to the cage it is also possible to prevent the cage or skip from crashing into the bottom of the shaft when lowering loads or hoisting out of balance. In order to increase the safety, the system may be improved by providing a resistance 19 in the controlling circuit, which resistance can be shunted or short-circuited by means of the electromagnetically- (Continued un page 1086.)