MUSEUM, REGISTER, JOURNAL, AND GAZETTE. No. 997.] SATURDAY, SEPTEMBER 17, 1842. [Price 3d. BUNNETT'S PATENT IMPROVEMENTS FOR INCREASING THE SAFETY OF RAILWAY TRAVELLING. BUNNETT'S PATENT IMPROVEMENTS FOR INCREASING THE SAfety of Sir,-No sooner does a serious accident occur on any of the lines of railway, which now intersect this country in all directions, than a general outcry is raised against the railway system, and mechanical expedients without number are suggested for preventing similar accidents in future. During the excitement which at such times prevails, it unfortunately happens that the parties more immediately interested in the safety of railway transit, have neither time nor inclination to investigate the comparative merits of the numerous crude suggestions with which they are then inundated. In calmer moments, however, I imagine that railway companies must feel themselves bound to consider with some degree of attention all the remedies that may be proposed for diminishing the dangers of railway travelling; and in order that these parties may have no excuse for remaining ignorant of any of the plans so put forward, it is desirable that these plans should have due publicity given to them by means of our scientific periodicals. The Mechanics' Magazine has strikingly lent itself to this national object, and I now beg permission to make use of its pages for the purpose of recording several important methods of increasing the safety of railway travelling which formed the subject of a patent granted to Mr. Joseph Bunnett, of Deptford, Civil Engineer, in the early part of 1841. These plans were briefly noticed in your pages (No. 939, vol. xxxv. p. 110,) at the time the specification was enrolled, but they will now be rendered better understood by means of the accompanying engravings;* of which fig. 1 shows a powerful break for the use of locomotive engines. a is a strong iron carriage for the breaks, laying flat against the side framings of the engine, bearing on and attached to the centre springs, and supported by, and also sliding freely through a staple bolted to the side frame, to allow for the play of the springs. b is a vertical shaft, on the lower end of which there is a worm taking into a worm-wheel keyed on a horizontal shaft Well finished explanatory models, one-eighth of full size, showing each matter in detail, may be inspected at Messrs. Bunnett and Corpe's Office, 26, Lombard-street, London. which passes across beneath the footplate; on this horizontal shaft are two pinions, c working into two racked sectors or levers d, placed one on each side of the engine opposite to the wheels. On turning the handle of the shaft b, and bringing the levers into the position shown, the breaks are brought down simultaneously on to the driving and trailing wheels of the engine. By turning the handle in the reverse direction, the breaks are removed from off the wheels and raised into the position shown by the dotted lines. The break bands are of steel, to the underside of which may be bolted two boxes, or segments fitted with wood or other elastic substances, if thought desirable. Attached to the fire-box of the engine is a bell f, on which, by means of a suitable arrangement of spring levers, one or more blows can be instantaneously struck by the guard on any carriage in the train, and the engine driver's attention called to any signal it may be necessary to make to him. The communication is continued throughout the train by means of horizontal rods lying along the top sides of the carriages connected together by short chains. Fig. 2 is side elevation of a railwaycarriage frame fitted at one end with a self-acting break, which it is proposed should be applied to all the wheels. a is a connecting-rod attached to the buffers; b is a bell crank, the axis of which is attached to the side frame of the carriage; c is a strong band or belt of leather, plaited hemp, wire rope, or other suitable material, to the underside of which (if necessary) plates of metal may be fastened; d is a curved spring, to one end of which, and to the bell-crank b, the band c is attached. Upon the buffer being driven in, the motion of the bell-crank b brings the band c down upon the periphery of the wheel with a force proportionate to the strength of the spring d, and the momentum of the moving mass. On the buffers resuming their original position, the band c is raised from off the wheels. The other end of figure 2 likewise shows the construction of a manual break. e is a vertical shaft and worm working into a worm-wheel on the end of a hori zontal shaft f, which gives motion to a pair of bevel wheels g, one of which is attached to a short vertical shaft carrying a pinion h; this pinion takes into two racks ii, kept in gear by friction rollers placed at the back; the ends of the racks are prolonged and attached to the centres of two bars lying across the carriage and carrying at each end a spring bow (kk) fitted, either with elastic bands of some suitable fabric, or boxes filled with wooden segments, &c. Fig. 3 shows another form of self-acting break; a a are strong iron rods attached to the centres of two cross-bars bb, the ends of which are attached to the back of the buffer-heads; the other ends of the rods a a, are forked, and embrace springs cc; the ends of these springs impinge against bars d d, laying across the carriage, the ends of which are fitted with boxes containing segments of wood or other suitable material, or with bows similar to k k in fig. 2. ƒ is a curved stay in the plane of action towards the centres of the wheels, on which are formed guides for the ends of the bars d d to move upon; the springs c c, and the bars d d, are shown in section. The rods a a, are capable of adjustment lengthways, so as to bring the breaks to bear upon the wheels when the buffers shall be forced in to any determined point. The action of these breaks on the wheels is simultaneous, and the force is equalized and regulated by the strength of the springs c c. The value and importance (in theory) of an efficient system of breaks for railway carriages has been constantly asserted in your pages, and it would, perhaps, be difficult to find a higher practical testimony to their immense advantagesespecially those of a self-acting description-than that given by Mr. George Stephenson, before a Select Committee of the House of Commons, in the following words: "Question 1319. By Mr. Labouchere.You have, of course, devoted much attention to the means of preventing accidents upon railways? "Answer.-I have. "Answer.-Certainly; the most important of anything that can be contrived for the safety of railway travelling. I believe, that if self-acting breaks were put upon every carriage, scarcely any accident could take place. "Question 1322.-What do you mean by self-acting breaks ? "Answer.-Whenever the power is taken off the engine by the engine-driver, it immediately ceases to proceed so fast; all the carriages immediately run towards the engine, with the impetus put into them before the engine was retarded. Every carriage, as it approaches the next carriage, shall apply the breaks itself. Every carriage is brought into the state of a sledge; the rolling motion of the wheels ceases; and supposing that an engine was running on with 12 or 14 coaches, and that every coach had a breaksman (that is, 12 coaches and 12 breaksmen), and the whole of them upon the look-out to see if anything went wrong in the engine, to apply the breaks immediately, I conceive that the self-acting principle is fifty times better." It will be seen that the action which Mr. Stephenson considered so desirable, is precisely that which distinguishes Mr. Bunnett's invention. Among other recommendations of Mr. Bunnett's breaks, is the entire absence of concussion on their application; being governed by the buffer springs, and formed of an elastic material, they entirely obviate the disagreeable jar, and harsh grating noise so frequently, and so justly complained of. Besides this, more or less force is in every case applied exactly as the exigencies of the case may require. Should the strength of the buffersprings be at any time insufficient to admit of backing a train, a very ready mode can be provided for preventing the action of the breaks upon the wheels. I remain, Sir, yours respectfully, 29, Alfred-street, Islington, MR. HALL'S LOCOMOTIVE SMOKE-BURNER. Sir, I had intended, this week, going into the several points referred to in my letter, inserted in your Magazine of the 3rd instant, with reference to Mr. Hall's pretensions, and his mode of admitting air to the furnaces of locomotive engines; but finding Mr. Hall disputes Mr. Kearsley's statement on this subject, I will not interfere, until the success or failure of Mr. Hall's plan be decided. As a mere matter of caution, on my part, this is manifestly called for, as I do not choose to point out either the errors he has com mitted in his mode of introducing the air, or suggest how he could remedy such error. For the present, then, I can only repeat that, when the dispute respecting Mr. Kearsley's report is decided, not by Mr. Hall's opinion, but by that of more impartial judges, I am prepared to prove my three propositions-1. That Mr. Hall's mode of introducing air is an infringement of my patent; 2. That he has carried it into practice so injudiciously, as to insure its failure; and 3. That it is cold, and not hot air which he introduces. These points being to be considered on purely scientific grounds, there can be no room for any personal matter or angry comment. But it is strange, in a matter based so exclusively on chemical considerations, as the peculiar modes of bringing the oxygen of the air into chemical union with the combustible gases evolved in a furnace, that those who dispute the correctness of my practice and details, will not discuss the question on chemical grounds, but fly away to the irrelevant points of the old practice, the acknowledged proportions among the parts of a furnace, and their areas and sections, &c. &c.; and, what is even still more irrelevant, dispute my right to give an opinion, as not being a professed engineer, or as presuming to know better than "operative engineers," or so-called "PRACTICAL" men. The real question at issue is, whether my facts or assertions be true or not. The merits of the question, as to the principles I have urged, are for the consideration of the chemical professor, and not for those who reject chemical considerations. With your permission, Sir, I will, from time to time, continue to put before your readers, not merely the chemical results of my practice, but the details of the practice itself. I am, Sir, yours, &c., Liverpool, September 8. C. W. WILLIAMS. LIFE ASSURANCE. Sir, The question I proposed (No. 989) in your highly useful journal, has been the means of producing some of the best written and truly important articles on Life Assurance that have ever appeared in your Magazine, or perhaps in any other periodical. My best thanks are due to Mr. George Scott for the multifarious calculations he has made on this highly important subject. The question has also been ably discussed by G. and Kinclaven. I am sure if any of these gentlemen had seen the prospectus of the West Middlesex Independent Life Assurance Society, they would soon have blown it up in your Magazine without the assistance of the renowned Sir Peter, and saved the deluded multitude many thousand pounds. If it would not put your scientific correspondents to too much trouble, I would esteem it a great favour if they would give their opinion upon the following little Table which I have copied from the prospectus of an Assurance Company. So far as I am enabled to judge, the annual premiums are higher than safety requires. Table of Annual Premiums for securing £100 to a child on attaining the age of 21. PLAN FOR THE APPLICATION OF THE STEAM POWER OF H. M. STEAMERS TO THE PROJECTION OF SHOT, AS WELL AS TO PROPELLING PUrposes. Sir,-Whilst I cannot but rejoice in the exertions of those well-intentioned individuals who are seeking to subdue and extinguish the spirit of war and the rage for conquest, and shall ever feel gratified at their success; yet still I have to lament that there appears every probability and prospect that the honournay, the existence of our empire will, at no great distance of time, require again the unfurling of the blood-stained banner of Mars. So long as France appears animated, as at present, with the restless and unsubdued ambition for military renown, combined with jealousy of our maritime superiority; whilst Russia continues to grow up, as it were, to the manhood of a vast military empire;* and whilst our descendants and neighbours across the Atlantic evince so pertinacious and crowing a disposition; even so long, Sir, as these facts and evidences exist, and appear to increase, will it be necessary to send forth our wooden, or rather iron walls, to maintain peace and good order. Impelled, Mr. Editor, therefore, by the force of these powerful arguments and unwelcome facts, I have great pleasure in submitting to your notice and approval a plan of propelling bullets and other projectiles by a mere breath of air. I dare say, Sir, that you well remember the "no small stir" and excitement produced when Mr. Perkins first brought out his steam gun, which, indeed, continues to be a very popular exhibition; no doubt, also, you are acquainted how that invention has never been turned to any practical account on a large scale. Now, Sir, the object of my addressing you is, to give a "local habitation and a name to a scheme bearing some resemblance to that of Mr. Perkins, which has been revolving in my mind, and not being able to discover any great objection to its practical application, I wish to record it in the most practical work of the age. The steam-engines on board steampackets have been constructed lately of immense size and power; two and three hundred horse-power engines have of late become general, and some there are See Alison's History of Europe. even of the power of four, five, and six hundred horses; indeed, there scarcely appears any limit to the size and power which may be given to these machines. What I propose is, that this enormous power, which in those vessels is always available, should be applied to the purpose of projecting balls, bullets, shells, &c., of what size, shape, or nature soever may be thought most desirable. The medium by which this power is to be transmitted from the engine to the projectile is atmospheric air, applied in a manner somewhat resembling the common air-gun. For the compression of the air I would have a series of air-pumps, through which the air should be passed from one to another; diminishing the diameter or bore of the pumps as the air becomes more compressed, and increasing the strength and thickness of the metal of the pumps in the same proportion; and either discharging the air from the gun as fast as it is supplied, or compressing it into a reservoir to be used when required, which reservoir I propose should be made of wrought-iron tubes, which, as is well known, can be made to sustain an immense pressure. For the discharge of the balls or bullets, I would either employ a similar apparatus to that of Mr. Perkins, or a peculiar construction which I have devised, by which a regular and continuous succession of balls can be supplied into the gun. As only one or two guns would be necessary for discharging an enormous quantity of balls, the guns required could be made of a length greater than usual, to obtain the full effect from the air expended, and at the same time secure greater accuracy of aim. There are various methods by which the paddles can be disconnected from the engine, which would answer equally well to connect the engine with the pumps for the compression of the air, so that the air-pumps and the paddle-wheels could. be worked either together or separately, as required. The whole apparatus is of simple construction, and the additional weight is but trifling; thus, the mighty power which drags along at one moment, the |