Langen, and have already sold, since the last stroke, the piston, in performing 1877, upwards of eight hundred of what one part of its stroke, draws in atmosare known as the Otto Silent Eugine, pheric air, after which it will draw in more than two thousand being the num- combustible mixture during the remainber sold in Great Britain and on the der of the stroke." These three strata Continent. The principle of action em- of gases are compressed in the return ployed, as indeed of nearly all the many stroke, and ignited, when the principle kinds since patented, is intended to meet above quoted comes into operation; and the difficulty of utilizing the energy of the next forward stroke does useful the gas consequent upon the sudden ex- work, the fourth, or next return stroke, plosion in former engines. The method expelling the product of combustion.. of doing this is best stated in the words The slide valve is made alternative in its of the specification of the English Pat- action, by being driven through a bevel ent, No. 2,081, 1876: "A combustible wheel on the main shaft of half the diamixture of gas or vapor and air is in- meter of that on the slide-valve rod. troduced into the cylinders, together The mixture used is 1 part of gas to 16 with air or other gas that may or may parts neutral; the latter being made of not support combustion in such a man- air and products of combustion in the ner that the particles of the combustible | proportion of 5 to 3. Some recent inmixture are more or less dispersed in an ventors adopt the main principle involved, isolated condition in the air or other gas, but they employ a separate compression so that on ignition, instead of an explo- cylinder, and by advertising a combussion ensuing, the flame will be communi- tion at each revolution, seem to imply cated gradually from one combustible the alternate action to be objectionable; particle to another, thereby effecting a and it must be confessed that the Otto gradual development of heat and a cor- engine is not perfectly regular in its acresponding gradual expansion of the tion with a light load, combustion taking gases, which will enable the motive place perhaps only once in five or six repower so produced to be utilized in the volutions. At the same time, with a most effective manner." Fig. 10, is a proper load and a moderately heavy flysectional plan taken from the same wheel, this is hardly appreciable, and is source, and is similar to the engine now of undoubted benefit to the cylinder, manufactured, except that a single in- which, being also single-acting, is therestead of a double crank is used. "The by only heated once in four strokes. cylinder is constructed of greater length One such engine has been running day than the stroke of the piston, so that and night at the Hinckley Gas Works there is a space beyond the latter when for fourteen months, this being equiva it is at end stroke. Assuming this space lent to three years' ordinary work, withto be filled with a portion of the gaseous out needing any repairs, which, notwithproducts of combustion resulting from standing the water-jacket surrounding these cylinders, is a satisfactory results and is contrary to many predictions concerning it. Such a result may possibly not attend those burning gas at every revolution. The latest trials of the amount of gas used are, according to Mr. Crossley, 24 cubic feet per hour per HP. for the 1 or HP. engines, and 18 cubic feet for the 16 HP. engines. The theory of gas engines is yet imperfect; but some things are certain with regard to them, and one is, that the absence of a boiler in connection with them gives a great advantage over the steam engine. The absence of risk either from explosion or conflagration is another strong point; while the scientific application of production on a large scale, in the form of the gas used, is perhaps the strongest of all, in leading to the conclusion that their present popularity is likely to last, gas engines being a step in the right direction. HYDRO-CARBON MOTORS. * Another engine, the Eclipse, of Messrs. Simon Beechey & Co., of Nottingham, with a separate compression cylinder, has a novel feature, in the use of steam, which is generated by the heat abstracted from the cylinder in order to keep it moderately cool. This steam is used in the cylinder not only to assist the action of the expanding gas-which it certainly luded to, although not much in use in Another class of engines must be aldoes, being capable of driving the en- this country, viz., hydro-carbon motors. gine for several minutes after the sup. In America, where petroleum is abundply of gas is turned off,--but it also acts as a lubricant, by which it is claimed ant, successful attempts have been made that a great saving in oil and tallow is thus to apply it, and its use is now rapeffected. Its action is fully described, is much the same as with a gas engine. idly extending. The principle of action and drawings are given in the "Engi- In the Brayton motor, described in "Enneer," 1879,* and the "Textile Manufacturer," May, 1879. In the former it is fibrous material soaked in petroleum, gineering, a jet of air is forced into stated that in a trial of one, the working and this substance is deposited on the cylinder, which was 8 inches in diamemeshes of wire gauge, from which it is ter, with 16 inches stroke, indicated 6.03 HP., and the compressing cylinder, evaporated. The vapor forms with the which was 7 inches in diameter, with 10 which is, as in the Otto silent engine, not supply of air a combustible mixture, inches stroke, indicated 1.87, leaving 4.16 HP. as the net indicated HP. of the en-bustion, with the attendant advantages. explosive, but admits of gradual comgine. The consumption of gas was from 22 to 26 cubic feet per IIP. per ly adopted; its appearance is similar to In Germany the Hock motor is commonThe objection to the foregoing type of an ordinary horizontal engine, and the engines is that they have to be started it as sucking in a small quantity of the German writer already quotedt describes by hand and turned through a revolu- fluid to about of its stroke, and also a tion or two; although the makers of the latter engine are said to have obviated certain quantity of air, when ignition and gradual expansion take place the necessity for this by an invention. Brayton's through the remaining. motor, in the article referred to, is said to use a gallon of crude petroleum per HP. per day of twelve hours, this of less than 3 HP. The Hock engine is amount being slightly exceeded in engines stated to use what is equivalent to 2.75 pounds of naphtha per hour per HP., at the cost of about 3d. per honr, a 1-HP. Petroleum motors may be advantageousengine being in first cost about £50. hour. With very small powers this objection is not felt, nor is it with a recent novelty, the Bisschop. This little motor, which is made from 1-man power upward, has had a sale of three hundred during the first nine months since its introduction: the consumption of gas is greater in proportion than in other larger gas engines, but its first cost is very small, and being advertised to work for d. per hour, although by no means a silent engine, it has decidedly met a long-felt ly used in place of gas engines where a want. * Vide vol. xlvii., p. 3. *"Engineering " vol. xxiii., p. 127. supply of gas cannot be obtained, and America and in Germany their use will where petroleum is abundant, but this probably increase, in this country, at eads to the conclusion that, although in present, it is not likely to do so. PNEUMATIC PROPELLER FOR RAILWAYS. By L. GONIN. From "Abstracts" of the Institution of Civil Engineers. carried by the engines on a line employing the compressed air system for helping trains up heavy gradients, is made to rise and fall so as to clear the chariot until beyond it. It is then dropped, and the chariot brought into work. The arrangement of valve described differs entirely from those of Clegg and Samuda, employedon the atmospheric and pneumatic railways, and it affords a tight joint, while it has not to be raised by, nor is it exposed to any wear by, the coulter. The latter is moreover double, one-half passing into the tube on either side of the valve, the strains upon it being thus of a simple order. THE author describes a new form of piston carries in front a small wheel valve and piston carriage for the tube of which runs upon and presses the iron a pneumatic railway. It is proposed to band down, and thus regulates its posiuse air compressed to 6 atmospheres, and tion for the passage of the coulter. The to apply the system, on grounds of econ- coulter may be either attached to a large omy and safety, to lines having heavy vehicle or, by the author's preference, gradients and but little level track. The to a small chariot running on separate tube is of cast iron provided with numer- rails on the top of the tube, and drawous exterior stiffening ribs, and fixed ing its load by chain connection, or the upon cross sleepers between the ordinary load may be pushed by a buffer. The rails, the latter being laid on longitu- corresponding buffer, which would be dinal resting on the transverse sleepers. The slot in the upper part of the tube is beveled on its interior edges, thus forming a seating for the continuous valve. The valve, made of greased leather, wrapped round a wooden body and having an iron band above and below, is in the form of a truncated wedge with the narrow end upwards, so that the pressure of the air within the tube may press the valve tightly into the wedge-formed sides of the longitudinal slot. The valve, when not pressed upwards by the air, hangs within the tube from a continuous flat band of iron, wide enough to overlap the slot in the tube, and to rest on the edges of the slot. Both iron band and valve are sufficiently flexible, their connection at a distance of some inches by bolts not materially affecting this quality. When the valve is in mid-position, vertically, so that the valve is clear below its seat, and the iron band is clear above the upper edge of the slot, there is room on each side of the connecting bolts for the passage of a double coulter piece, connecting the piston in the tube with the carriage above, which is driven by it. The part of the valve at and behind the piston is kept up in its highest position by the compressed air, while the part ahead of the piston falls to its lowest position. The carriage driven by the As the quantity of power required for compressing air does not increase with the increase of pressure, but in proportion to the logarithm of the pressures, the author proposes pressure as high as from 6 to 10 atmospheres, so that the air may be employed expansively, the full pressure being used for starting and traveling the greater part of the journey on inclines; the air would then be cut off, and the remainder of the journey performed by expansion. An experimental length of tube, 10 inches in diameter and 131 feet in length, has been constructed, the results of experiments with which are given. NOTE ON THE PRESENT SYSTEM OF exception of the Lyons company, the PERMANENT WAY ON THE SIX CHIEF weight of the flange rail track is about RAILWAYS OF FRANCE.-By E. Lecocq. 323 lbs. per yard, while the double-head-Steel rails are now almost exclusively ed way attains a mean weight of 403 used, but the section and weight of rail lbs. per yard. This excess of 80 lbs. per differ widely. The Eastern, the North- yard is considered by the author to be ern, and the Paris, Lyons, and Mediter- eminently favorable to stability, especialranean companies use only the flange ly with the heavy loading and great rail; but the Orleans, the Midland and speed of modern trains. Western use also the old double-headed rail. The flange rail used on the Northern, and on recent extensions of the Western lines, weighs 60 lbs. per yard, and is noticeable chiefly for the small width of the base (31 inches), as compared with the height (5 inches bare). This The following are matters of details not shown in the table, but considered worthy of notice: 1. Four bolts are now invariably used for fishing, instead of three, as was commonly the case some time ago. 2. Grooved fishes are used by three of type of rail was introduced on the the companies; the others use shoulder Northern some six years ago, so presumably it has proved satisfactory. The Eastern company uses also a 60 lbs. rail, but the height is reduced to 4 inches, and the base increased to nearly 4 inches. The Lyons company employs two sections, the heavier one weighing 77 lbs. per yard, and measuring 53 inches high, by 5 inches wide, and the lighter one weighing 66 lbs. per yard, and measuring 5 inches by 4 inches base. The width of head as a rule is 2 inches, and the length of rail about 26 feet. With the exception of some practically obsolete types of " pear headed rail, the angle for fishing is to 1, and the thickness of web in most instances is rather less than inch. bolts. 3. Wood screws are exclusively used for fastening the rails and chairs by the Eastern, Northern, and Western companies, and by the Lyons company for their lighter rail. Trenails are still used for fastening the chairs by the Southern and Orleans companies. The Lyons company fasten their heavy rail with a fang bolt on the outside, and a trenail on the inside of the 5 inches flange.Revue générale des Chemins de fer. It is well known that ordinary letter paper if rubbed acquires electric properties. M. Wideman, has, however, says the Electrician, found that if one takes Swedish filter paper, or this paper laid between pieces of letter paper, and subjects it to the following treatment, it displays strong electric properties, and sparks several centimeters in length can be obtained: The paper should be plunged into a mixture of nitric acid and sulphuric acid of equal volume. The paper thus pyroxilized is then washed in plenty of water and dried. Then rub quickly, having stretched it on a waxed cloth, in order to give it electric properties. Nearly every experiment with static electricity can be accomplished with the paper. THE people of Portage La Prairie have consented to make a branch line to the Canada Pacific Railway of five miles in length, if the Government would furnish rails and rolling stock, and to hand it over to the Government on completion. NOTES ON RAILROADING. By J. A. L. WADDELL, C. E. From the Papers of the Pi Eta Society of Rensselaer Polytechnic Institute. THE subject with which I beg leave to | which the road is to be built, whether for occupy your attention this evening and, passenger or freight traffic, and, if for if such be your pleasure, at some future the latter, whether it is to be heavy or meetings also, is that of Railroading. It light. This influences the grades, and, is not my intention to cover in these therefore, also the length and cost of the notes the whole subject of Railroad En- road. The heavier the traffic, the more gineering, but simply to convey to you, expensive will usually be the first cost of who are soon to become engineers, an construction, for hills will have to be idea of what practical railroading really avoided or cut through, that would is, in order that you may not feel at a loss how to proceed should you, at any time, be called upon to take charge of a survey or construction party. The facts here stated have been obtained principally from personal observation and experience, and I have avoided as much as possible dealing with those parts of the subject that are treated in standard works; nevertheless for the purpose of making what I have written clear and continuous, I have had to touch lightly upon some of them. In dealing with such a technical subject as this one, it is impossible to avoid repetition of certain words and expressions, so you will please make all due allowance for the phraseology of what I am about to read to you, and do not expect to hear the flowing language and easy style which one might employ in dealing with a literary subject. Especial reference is made to bush work," for by far the larger portion of American railroading partakes of that character; besides, nearly all the difficulties met with in running a line through a well-settled country or prairie land are encountered in the bush, in addition to many others of an entirely different nature. The building of a line of road may be divided into four distinct steps, which will be treated separately; they are Exploration, Preliminary, Location and Construction. EXPLORATION. The data usually given to the engineer who makes the exploratory survey, are the terminii of the line, various points through which it is to pass, and the general character of the road. The latter is determined by the principal object for VOL. XXIV. No. 4-20. otherwise have been run over, thus augmenting the expense by reason of either the increased length of line or the greater quantity of material to be moved. On most roads the heavy freight goes in one direction, so in that direction the upgrades should, if possible, be the lightest. Another reason for having two maximum grades is that, in case a summit is to be reached, the engineer, by having a light maximum down grade in the direction of the line, will be prevented from making the profile too irregular. Having given, then, the terminii, intermediate points and perhaps also the maximum grades, an exploratory survey is madeby an experienced engineer passing over the country, so as to report whether, in his opinion, a practicable route can be found, and, if so, what would be its approximate location. If the character of the country permit, he travels on horseback; though usually, it is necessary to go on foot, in which case he is accompanied by one or two packmen. His equipment need consist only of an axe, a pair of field glasses, a note book, a hand level or two barometers and a pair of steel climbers to enable him to climb a tree with facility. By means of the latter he will often be able to obtain a good knowledge of the country, and to take such general observations as may be of use in the preliminary survey. He must estimate distances and elevations, or obtain the latter by means of the barometers or hand level, make notes as to the course of rivers and streams and their crossings, establish the general direction of the chains of hills, locate passes, look out for water communication or some other way to obtain access to the differ |