1020 THE COLLIERY GUARDIAN. November 13, 1914. operated by two cams only. These cams, together with rollers and pins, are manufactured of special steel and then hardened and ground to limit gauges. All these items are necessary factors to obtain the efficiencies demanded from the Crossley gas engine, but another still remains, which requires some explana- tion, namely, the method of gas engine governing; the economical governing of the engine at all loads being of supreme importance. This we accomplish by vary- ing the lift of the charge admission valve by means of a movable fulcrum, the timings of opening and closing remaining constant for all lifts. Returning again to the subject of waste fuels, it will interest you to know that under actual working con- ditions we have obtained the following consumptions in our producers :— Lb. per B.H.P. per hour. Coke breeze .................. 1 Charcoal ..................... 1 Cotton seed .................. 2| Bark refuse up to 50 per cent. moisture.................... 4 Tan i efuse................... 4 Peat ........................ 3-3 Lignite ........................ 1*75 Peat briquettes ............. 1'25 These figures, if corrected for indicated horse power, will be about 15 per cent, better; the practice of gas engines to give the actual horse power or horse power developed, termed b.h.p., at the engine crank shaft on the friction brake or other type of power recorder is being taken up more generally by steam engine builders, and is, in our opinion, the best method for determining the size of engine required, as it is based on the mechanical efficiency. As a general rule gas engines using ordinary fuels are sold with a margin of 10 per cent, for overload. It is therefore important always carefully to estimate what the maximum overload or peak load may be, as we find that sometimes a larger margin than 10 per cent.' is required. At the termination of the existing European War we shall again meet keen and persistent foreign competition in all the markets of the world. Can we afford any longer to ignore the advantages which our competitors have utilised, and which are ours if only we will put out our hands to grasp them? We find that in the flourishing iron districts of Westphalia and Rhineland practically no power gas is wasted, where instead of polluting the atmosphere as we do, cheap electrical power is available for all manufacturing purposes. Again, in the notorious works of Messrs. Krupp’s, there are 26 gas engines at this moment running on blast- furnace gas developing 36,000 electrical horse power per hour; and is it not because Germany is utilising these power resources that we shall find Germany hard to beat, whether in w’ar or commerce? In our common bituminous coal or slack there is proved to be another hidden source of wealth in the nitrogen it contains, of which about 70 per cent, is recoverable. Discussion. Mr. A. T. Jenkins, J.P., the president of the society, who was in the chair, speaking at the conclusion of the lecture, said from what Mr. Coster had told them, that they would be lighting the town with electricity generated from the utilisation of road sweepings before long, the waste which had been allowed to go on was a loss not merely to the individual, but to the whole community. He' was afraid that the poorest of manu- facturers had the greatest w’aste, because they often had to keep to antiquated methods and appliances, and therefore had not the ghost of a chance in competition with better equipped firms. Mr. A. Leigh said he was sure that if the English manufacturers decided to compete boldly in the markets at present supplied to a great extent by Germany, we should have a very good chance of capturing their trade, especially as far as gas engines were concerned. Some people thought that gas engines were a very great trouble, but he was afraid that in many cases the trouble was caused through them not knowing how to attend to the engine. A discussion took place, to which Messrs. Baker, W. Berry, A. H. Smitheman, and Arthur Habershon con- tributed. Mr. Coster, in reply, said the problem of the utilisa- tion of these waste gases was one that the manufac- turers in this country should instantly take hold of. It was tackled in Germany 30 years ago, and they were a long way in advance of us, so that we should be com- pelled to take it up very quickly if we were going to hold our own in the markets of the world. He did not attempt to say that the gas engine was going to sweep out the steam engine; he did not think for a moment it ever would. The steam engine would always have its place, but, at the same time, he thought there had been great neglect on -the part of this country in the use of the gas engine. With regard to what had been said about the use of town sweepings, he might tell them that there was a shipyard on the north-east coast where his firm were going to put in a producer to use the sweepings from the shipyard. There was a stock of waste wood and refuse from ships under repair that the owners had not known what to do with, and now Messrs. Crossley Brothers were going to put in a producer and turn it into power for them. So that instead of being a nuisance and a cost in carting loads of it away, they were going to get at least 200-horse power out of it. Messrs. Crossley Brothers had not put any gas engines in the Lancashire cotton mills, but there was a gat engine installed in a cotton mill at Stalybridge, ant. there were gas engines in use in Japan in this industry. The time would come, he thought, when gas engines would be utilised more for cotton mill driving. APPROVED SAFETY LAMPS. In pursuance of section 33 of the Coal Mines Act, 1911, the Home Secretary has made an Order approving certain new types of safety lamps until further Order, for use in all mines to which the Act applies, subject in each case to the conditions specified in the schedule to the Order. There are also modifications in the speci- fications in former Orders. The Order may be cited as “ The Safety Lamps Order of October 7, 1914.” I.—Flame Safety Lamps for Use by Officials Only. Messrs. J. H. Rothwell and Company’s “ A 1,” “ A 2,” “Cl,” and “02” Lamps. These lamps are modifications of Messrs. J. H. Roth- well and Company’s “ A ” and “ C ” lamps. The description of the “Al” and “ A 2 ” lamps is the same as the description of the “ A ” lamp,* and the descrip- tion of the “ Cl ” and “ C 2 ” lamps is the same as the description of the “ C ” lamp,* with the following varia- tions :— (1) The Crown and Bonnet may be of aluminium or brass. In the “ A 2 ” and “ C2 ” lamps the bonnet is provided with three channels with openings at the top, each not more than 0-30 sq. in. in area, for the admission of air, as shown in fig. 1. Types 4 x and c 2. Fig. 1 New design of shield for gas-testing purposes and new design of magnetic lock applicable to types A and C lamps (J. H. Rothwell and Company), and Nos. 1, 2 and 4 lamps (W. E. 1'eale and Company Limited). (2) The Middle Ring, Bottom Ring, Glass Retaining Ring, and Oil Vessel may be of aluminium; and the middle ring may be provided with a brass or aluminium shut-off ring, and with horizontal air inlet holes of total area not exceeding 0-5 sq. in. : the gauzes being pro- tected from a direct horizontal current by a flange of the outer gauze ring. (3) The Gauzes may be of copper in the case of lamps used for surveying purposes. Each lamp must have been made by Messrs. J. H. Rothwell and Company, at their Sindsley Works at Swinton, near Manchester. II.—Electric Safety Lamps for General Use. The Bristol Safety Lamp, Type B.T. 4 V. The Bristol Safety Lamp, Type B.T. 4 V, the general design of which is shown in fig. 2, possesses the follow- ing essential features :— (1) A case of steel, brass, aluminium, or aluminium alloy. (2) An electrical accumulator, fitted with two terminal lugs, and so constructed as to prevent escape of the liquid, whatever the position of the lamp, whilst allow- ing the escape of gas generated by chemical action. (3) A cover of steel, brass, aluminium, or aluminium alloy, hinged to the case and secured thereto by a screw bolt : provided that the cover forms a flame tight con- nection with the case. A bezel or base plate of alumi- nium or brass, secured to the cover, carries the incandescent bulb, reflector, protecting glass, and guard. The protecting glass is securely cemented to a metal glass retaining ring, with which it forms a dame- tight connection. The retaining ring is screwed to the base plate and securely locked to a brass slide by means of a metal pin. The slide is held in the locked position, when the cover is closed, by means of another metal pin on the upper edge of the case, which projects through the case and engages a hole in the slide. The slide bracket is screwed to the cover from the inside. (4) A flametight switch of either of the types shown in fig. 2, consisting of :—(a) A metal sliding plate, the out- ward movement of which is limited by a pin; or (b) a * See Colliery Guardian, October 10, 1913, p. 737. rotary or partially rotary stem, working in a tube. The movement of the stem is limited by a pin. A flame- tight joint between the external end of the tube and the head of the stem is maintained by a washer of vulcanite or other suitable material, close contact being ensured by a spiral spring. Fig. 2.—The Bristol Safety Lamp. Type BT4V. (5) A lead rivet lock of any of the types shown in fig- 2. It is provided that the total weight of the lamp shall not be more than 4| lb. The lamp is made at the Bristol Electric Safety Lamp Works at 40, Great Smith-street, Westminster. The Manley and Sandy (M. and S.) Miners’ Electric Safety Lamp (with Electric Gas Indicator). This lamp, the general design of which is shown in fig. 3, possesses the following essential features :— (1) A sheet steel securely soldered battery case. Electric Indicator Switch Fig. 3.—Manley and Sandy Miners' Electric Safe-iy Lamp. With electric gas indicator. (2) An electrical accumulator, so constructed as to prevent escape of the liquid whatever the position of the lamp, whilst allowing the escape of gas generated by chemical action. (3) A hinged sheet steel securely soldered cover,