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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

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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 80 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 Ottó 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 equivait 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 The theory of gas engines is yet imand is contrary to many predictions con- perfect; but some things are certain cerning it. Such a result may possibly with regard to them, and one is, that not attend those burning gas at every re- the absence of a boiler in connection volution.

with them gives a great advantage over The latest trials of the amount of gas the steam engine. The absence of risk used are, according to Mr. Crossley, 24 either from explosion or conflagration is cubic feet per hour per HP. for the 1 or another strong point; while the scientific

HP. engines, and 18 cubic feet for the application of production on a large 16 HP. engines.

scale, in the form of the gas used, is Another engine, the Eclipse, of Messrs. perhaps the strongest of all, in leading Simon Beechey & Co., of Nottingham, to the conclusion that their present popwith a separate compression cylinder, ularity is likely to last, gas engines behas a novel feature, in the use of steam, ing a step in the right direction. which is generated by the heat abstracted from the cylinder in order to keep it moderately cool. This steam is used in

HYDRO-CARBON MOTORS. 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 idly extending. The principle of action effected. Its action is fully described, is much the same as with a gas engine. 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 gineering, ** a jet of air is forced into stated that in a trial of one, the working and this substance is deposited on the

fibrous material soaked in petroleum, cylinder, which was 8 inches in diame meshes 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 supply, of air a combustible mixture, inches stroke, indicated 1.87, leaving 4.16

which is, as in the Otto silent engine, not HP. as the net irdicated HP. of the en

explosive, but admits of gradual comgine. The consumption of gas was In Germany the Hock motor is common

bustion, with the attendant advantages. from 22 to 26 cubic feet per HP. per ly adopted; its appearance is similar to hour.

The objection to the foregoing type of an ordinary horizontal engine, and the engines is that they have to be started German writer already quotedt describes

it as sucking in a small quantity of the tion or two; although the makers of the fluid to about of its stroke, and also a tion or two; although the makers of the certain quantity of air, when ignition latter engine are said to have obviated the necessity for this by an invention.

and gradual expansion take place With very small powers this objection is through the remaining . Brayton's not felt, nor is it with a recent novelty, motor, in the article referred to, is said

use a gallon of crude petroleum the Bisschop. This little motor, which is made from 1-man power upward, has per HP: per day of twelve hours, this had a sale of three hundred during the of less than 3 HP. The Hock engine is

amount being slightly exceeded in engines first nine months since its introduction: the consumption of gas is greater in stated to use what is equivalent to 2.75 proportion than in other larger gas en; the cost of about 3d. per honr, a 1-HP.

pounds of naphtha per hour per HP., at gines, but its first cost is very small, and being advertised to work for 2d. per Petroleum motors may be advantageous

engine being in first cost about £50. 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.

Engineering " vol. xxiii., p. 127.

to

* Vide vol. xlvii., p. 3.

+"
“ Klein-Kraft-Maschinen," p. 32.

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.

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 inay be pushed by a buffer. The rails, the latter being laid on longitu- corresponding buffer, which would be dinal resting on the transverse sleepers. carried by the engines on a line employThe slot in the upper part of the tube is ing the compressed air system for helpbeveled on its interior edges, thus forming trains up heavy gradients, is made ing a seating for the continuous valve. to rise and fall so as to clear the chariot The valve, made of greased leather, until beyond it. It is then dropped, and wrapped round a wooden body and have the chariot brought into work. The aring an iron band above and below, is in rangement of valve described differs enthe form of a truncated wedge with the tirely from those of. Clegg and Samuda, narrow end upwards, so that the press- employedon the atmospheric and pneuure of the air within the tube may press matic railways,and it affords a tight joint, the valve tightly into the wedge-formed while it has not to be raised by, nor is it sides of the longitudinal slot. The valve, exposed to any wear by, the coulter. The when not pressed upwards by the air, latter is moreover double, one-half passhangs within the tube from a continuous ing into the tube on either side of the flat band of iron, wide enough to overlap valve, the strains upon it being thus of a the slot in the tube, and to rest on the simple order. edges of the slot. Both iron band and As the quantity of power required for valve are sufficiently flexible, their con compressing air does not increase with nection at a distance of some inches by the increase of pressure, but in proporbolts not materially affecting this quality. tion to the logarithm of the pressures, When the valve is in mid-position, verti- the author proposes pressure as high as cally, so that the valve is clear below its from 6 to 10 atmospheres, so that the air seat, and the iron band is clear above the may be employed expansively, the full upper edge of the slot, there is room on pressure being used for starting and each side of the connecting bolts for the traveling the greater part of the journey passage of a double coulter piece, con on inclines; the air would then be cut necting the piston in the tube with the off, and the remainder of the journey carriage above, which is driven by it. performed by expansion. An experiThe part of the valve at and behind the mental length of tube, 10 inches in piston is kept up in its highest position diameter and 131 feet in length, has by the compressed air, while the part been constructed, the results of experiahead of the piston falls to its lowest ments with which are given. position. The carriage driven by the

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 The following are matters of details rail. The flange rail used on the North- not shown in the table, but considered ern, and on recent extensions of the West- worthy of notice: ern lines, weighs 60} lbs. per yard, and 1. Four bolts are now invariably used is noticeable chiefly for the small width for fishing, instead of three, as was comof the base (313 inches), as compared monly the case some time ago. with the height (5 inches bare). This 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 presum- bolts. ably it has proved satisfactory.

3. Wood screws are exclusively used The Eastern company uses also a 601 for fastening the rails and chairs by the lbs. rail, but the height is reduced to 4 Eastern, Northern, and Western compainches, and the base increased to nearly nies, and by the Lyons company for 4 inches.

their lighter rail. Trenails are still used The Lyons company employs two sec- for fastening the chairs by the Southern tions, the heavier one weighing 773 lbs. and Orleans companies. The Lyons per yard, and measuring 5] inches high, company fasten their heavy rail with a by 5} inches wide, and the lighter one fang bolt on the outside, and a trenail weighing 664 lbs. per yard, and measur- on the inside of the 54 inches flange.ing 5 inches by 4 inches base.

Revue générale des Chemins de fer. The width of head as a rule is 21 inches, and the length of rail about 26 It is well known that ordinary letter feet. With the exception of some prac. paper if rubbed acquires electric propertically obsolete types of "pear headed” ties. M. Wideman, has, however, says rail, the angle for fishing is to 1, and the Electrician, found that if one takes the thickness of web in most instances Swedish filter paper, or this paper laid is rather less than £ inch.

between pieces of letter paper, and subA diagram and table, illustrating the jects it to the following treatment, it arrangement of the sleepers and joints, displays strong electric properties, and lead to the following conclusions: sparks several centimeters in length can

1. Suspended joints are adopted by be obtained : The paper should be five out of the six companies, the North- plunged into a mixture of nitric acid ern alone putting a sleeper under the and sulphuric acid of equal volume. joint.

The paper thus pyroxilized is then 2. The spacing of the sleepers next washed in plenty of water and dried. the joint is always about 2 feet from Then rub quickly, having stretched it on center to center.

a waxed cloth, in order to give it electric 3. On the Lyons and on the Western properties. Nearly every experiment railways, the 'sleepers next to those at with static electricity can be accompthe joint are spaced a less distance apart lished with the paper. than the remainder. This also is necessarily the case on the Eastern and Northern lines, because the fish-joints are not The people of Portage La Prairie opposite each other, but lap about 2 have consented to make a branch line to feet.

the Canada Pacific Railway of five miles 4. Expedients to prevent the longitu- in length, if the Government would furdinal movement of the rails are adopted nish rails and rolling stock, and to hand by five out of the six companies. it over to the Government on comple

5. Finally, it appears that, with the tion.

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, au 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 otherwise have been run over, thus aug. loss how to proceed should you, at any menting the expense by reason of either time, be called upon to take charge of a the increased length of line or the greater survey or construction party. The facts quantity of material to be moved. On here stated have been obtained princi- most roads the heavy freight goes in one pally from personal observation and ex- direction, so in that direction the upperience, and I have avoided as much as grades should, if possible, be the lightest. possible dealing with those parts of the Another reason for having two maxisubject that are treated in standard mum grades is that, in case a summit is works; nevertheless for the purpose of to be reached, the engineer, by having a making what I have written clear and light maximum down grade in the direccontinuous, I have had to touch lightly tion of the line, will be prevented from upon some of them. In dealing with making the profile too irregular. Havsuch a technical subject as this one, it is ing given, then, the terminii, intermediimpossible to avoid repetition of certain ate points and perhaps also the maximum words and expressions, so you will please grades, an exploratory survey is made make all due allowance for the phraseol- by an experienced engineer passing over ogy of what I am about to read to you, the country, so as to report whether, in and do not expect to hear the flowing his opinion, a practicable route can be language and easy style which one might found, and, if so, what would be its apemploy in dealing with a literary sub-proximate location. If the character of ject. Especial reference is made to the country permit, he travels on horsebush work,” for by far the larger por- back; though usually, it is necessary to tion of American railroading partakes of go on foot, in which case he is accompathat character; besides, nearly all the nied by one or two packmen. His equipdifficulties met with in running a line' ment need consist only of an axe, a pair through a well-settled country or prairie of field glasses, a notebook, a hand land are encountered in the bush, in ad- level or two barometers and a pair of dition to many others of an entirely dif- steel climbers to enable him to climb a ferent nature. The building of a line of tree with facility. By means of the latroad may be divided into four distinct ter he will often be able to obtain a good steps, which will be treated separately; knowledge of the country, and to take they are Exploration, Preliminary, Loca- such general observations as may be of tion and Construction.

use in the preliminary survey. He must

estimate distances and elevations, or obEXPLORATION.

tain the latter by means of the barome. The data usually given to the engineer ters or hand level, make notes as to the who makes the exploratory survey, are course of rivers and streams and their the terminii of the line, various points crossings, establish the general direction, through which it is to pass, and the gen- of the chains of hills, locate passes, look eral character of the road. The latter is out for water communication or some determined by the principal object for other way to obtain access to the differ

VOL. XXIV.No. 4-20.

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