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A Catechism of the Steam Engine
by John Bourne
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709. Q.—When you described the operation of boring the cylinder, you stated that the cylinder, when laid upon its side, became oval; will not this change of figure distort the cylinder face?

A.—It is not only in the boring of the cylinder that it is necessary to be careful that there is no change of figure, for it will be impossible to face the valves truly in the case of large cylinders, unless the cylinder be placed on end, or internal props be introduced to prevent the collapse due to the cylinder's weight. It may be added, that the change of figure is not instantaneous, but becomes greater after some continuance of the strain than it was at first, so that in gauging a cylinder to ascertain the difference of diameter when it is placed on its side, it should have lain some days upon its side to ensure the accuracy of the operation.

710. Q.—How is any flaw in the valve or cylinder face remedied?

A.—Should a hole occur either in the valve, in the cylinder, or any other part where the surface requires to be smooth, it may be plugged up with a piece of cast iron, as nearly as possible of the same texture. Bore out the faulty part, and afterward widen the hole with an eccentric drill, so that it will be of the least diameter at the mouth. The hole may go more than half through the iron: fit then a plug of cast iron roughly by filing, and hammer it into the hole, whereby the plug will become riveted in it, and its surface may then be filed smooth. Square pieces may be let in after the same fashion, the hole being made dovetailed, and the pieces thus fitted will never come out.

711. Q.—When cylinders are faced with brass, how is the face attached to the cylinder?

A.—Brass faces are put upon valves or cylinders by means of small brass screws tapped into the iron, with conical necks for the retention of the brass: they are screwed by means of a square head, which, when the screw is in its place, is cut off and filed smooth. In some cases the face is made of extra thickness, and a rim not so thick runs round it, forming a step or recess for the reception of brass rivets, the heads of which are clear of the face.

712. Q.—What is the best material for valve faces?

A.—Much trouble is experienced with every modification of valve face; but cast iron working upon cast iron is, perhaps, the best combination yet introduced. A usual practice is to pin brass faces on the cylinder, allowing the valve to retain its cast iron face. Some makers employ brass valves, and others pin brass on the valves, leaving the cylinder with a cast iron face. If brass valves are used, it is advisable to plane out two grooves across the face, and to fill them up with hard cast iron to prevent rutting. Speculum metal and steel have been tried for the cylinder faces, but only with moderate success. In some cases the brass gets into ruts; but the most prevalent affection is a degradation of the iron, owing to the action of the steam, and the face assuming a granular appearance, something like loaf sugar. This action shows itself only at particular spots, and chiefly about the angles of the port or valve face. At first the action is slow; but when once the steam has worked a passage for itself, the cutting away becomes very rapid, and, in a short time, it will be impossible to prevent the engine from heating when stopped, owing to the leakage of steam through the valve into the condenser. Copper steam pipes seem to have some galvanic action on valve faces, and malleable iron pipes have sometimes been substituted; but they are speedily worn out by oxidation, and the scales of rust which are carried on by the steam scratch the valves and cylinders, so that the use of copper pipes is the least evil.

713. Q.—Will you explain in what manner the joints of an engine are made?

A.—Rust joints are not now much used in engines of any kind, yet it is necessary that the engineer should be acquainted with the manner of their formation. One ounce of sal-ammoniac in powder is mingled with 18 ounces or a pound of borings of cast iron, and a sufficiency of water is added to wet the mixture thoroughly, which should be done some hours before it is wanted for use. Some persons add about half an ounce of flowers of brimstone to the above proportions, and a little sludge from the grindstone trough. This cement is caulked into the joints with a caulking iron, about three quarters of an inch wide and one quarter of an inch thick, and after the caulking is finished the bolts of the joints may be tried to see if they cannot be further tightened. The skin of the iron must, in all cases, be broken where a rust joint is to be made; and, if the place be greasy, the surface must be well rubbed over with nitric acid, and then washed with water, till no grease remains. The oil about engines has a tendency to damage rust joints by recovering the oxide. Coppersmiths staunch the edges of their plates and rivets by means of a cement formed of pounded quicklime, with serum of blood, or white of egg; and in copper boilers such a substance may be useful in stopping the impalpable leaks which sometimes occur, though Roman, cement appears to be nearly as effectual.

714. Q.—Will you explain the method of case hardening the parts of engines?

A.—The most common plan for case hardening consists in the insertion of the articles to be operated upon among horn or leather cuttings, hone dust, or animal charcoal, in an iron box provided with a tight lid, which is then put into a furnace for a period answerable to the depth of steel required. In some cases the plan pursued by the gunsmiths may be employed with convenience. The article is inserted in a sheet iron case amid bone dust, often not burned; the lid of the box is tied on with wire, and the joint luted with clay; the box is heated to redness as quickly as possible and kept half an hour at a uniform heat: its contents are then suddenly immersed in cold water. The more unwieldy portions of an engine may be case hardened by prussiate of potash—a salt made from animal substances, composed of two atoms of carbon and one of nitrogen, and which operates on the same principle as the charcoal. The iron is heated in the fire to a dull red heat, and the salt is either sprinkled upon it or rubbed on in a lump, or the iron is rubbed in the salt in powder. The iron is then returned to the fire for a few minutes, and finally immersed in water. By some persons the salt is supposed to act unequally, as if there were greasy spots upon the iron which the salt refused to touch, and the effect under any circumstances is exceedingly superficial; nevertheless, upon all parts not exposed to wear, a sufficient coating of steel may be obtained by this process.

715. Q.—What kind of iron is most suitable for the working parts of an engine?

A.—In the malleable iron work of engines scrap iron has long been used, and considered preferable to other kinds; but if the parts are to be case hardened, as is now the usual practice, the use of scrap iron is to be reprehended, as it is almost sure to make the parts twist in the case hardening process. In case hardening, iron absorbs carbon, which causes it to swell; and as some kinds of iron have a greater capacity for carbon than other kinds, in case hardening they will swell more, and any such unequal enlargement in the constituent portions of a piece of iron will cause it to change its figure. In some cases, case hardening has caused such a twisting of the parts of an engine, that they could not afterward be fitted together; it is preferable, therefore, to make such parts as are to be case hardened to any considerable depth of Lowmoor, Bowling, or Indian iron, which being homogeneous will absorb carbon equally, and will not twist.

716. Q.—What is the composition of the brass used for engine bearings?

A.—The brass bearings of an engine are composed principally of copper and tin. A very good brass for steam engine bearings consists of old copper 112 lbs., tin 12-1/2 lbs., zinc 2 or 3 oz.; and if new tile copper be used, there should be 13 lbs. of tin instead of 12-1/2 lbs. A tough brass for engine work consists of 1-1/2 lb. tin, 1-1/2 lb. zinc, and 10 lbs. copper; a brass for heavy bearings, 2-1/2 oz. tin, 1/2 oz. zinc, and 1 lb. copper. There is a great difference in the length of time brasses wear, as made by different manufacturers; but the difference arises as much from a different quantity of surface, as from a varying composition of the metal. Brasses should always be made strong and thick, as when thin they collapse upon the bearing and increase the friction and the wear.

717. Q.—How is Babbitt's metal for lining the bushes of machinery compounded?

A.—Babbitt's patent lining metal for bushes has been largely employed in the bushes of locomotive axles and other machinery: it is composed of 1 lb. of copper, 1 lb. regulus of antimony, and 10 lbs. of tin, or other similar proportions, the presence of tin being the only material condition. The copper is first melted, then the antimony is added, with a small proportion of tin-charcoal being strewed over the surface of the metal in the crucible to prevent oxidation. The bush or article to be lined, having been cast with a recess for the soft metal, is to be fitted to an iron mould, formed of the shape and size of the bearing or journal, allowing a little in size for the shrinkage. Drill a hole for the reception of the soft metal, say 1/2 to 3/4 inch diameter, wash the parts not to be tinned with a clay wash to prevent the adhesion of the tin, wet the part to be tinned with alcohol, and sprinkle fine sal-ammoniac upon it; heat the article until fumes arise from the ammonia, and immerse it in a kettle of Banca tin, care being taken to prevent oxidation. When sufficiently tinned, the bush should be soaked in water, to take off any particles of ammonia that may remain upon it, as the ammonia would cause the metal to blow. Wash with pipe clay, and dry; then heat the bush to the melting point of tin, wipe it clean, and pour in the metal, giving it sufficient head as it cools; the bush should then be scoured with fine sand, to take off any dirt that may remain upon it, and it is then fit for use. This metal wears for a longer time than ordinary gun metal, and its use is attended with very little friction. If the bearing heats, however, from the stopping of the oil hole or otherwise, the metal will be melted out. A metallic grease, containing particles of tin in the state of an impalpable powder, would probably be preferable to the lining of metal just described.

718. Q.—Can you state the composition of any other alloys that are used in engine work?

A.—The ordinary range of good yellow brass that files and turns well, is about 4-1/2 to 9 ounces of zinc to the pound of copper. Flanges to stand brazing may be made of copper 1 lb., zinc 1/2 oz., lead 3/8 oz. Brazing solders when stated in the order of their hardness are:-three parts copper and one part zinc (very hard), eight parts brass and one part zinc (hard), six parts brass, one part tin, and one part zinc (soft); a very common solder for iron, copper, and brass, consists of nearly equal parts of copper and zinc. Muntz's metal consists of forty parts zinc and sixty of copper; any proportions between the extremes of fifty parts of zinc and fifty parts copper, and thirty-seven zinc and sixty-three copper, will roll and work at a red heat, but forty zinc to sixty copper are the proportions preferred. Bell metal, such as is used for large bells, consists of 4-1/2 ounces to 5 ounces of tin to the pound of copper; speculum metal consists of from 7-1/2 ounces to 8-1/2 ounces of tin to the pound of copper.



ERECTION OF ENGINES.

719. Q.—Will you explain the operation of erecting a pair of side lever engines in the workshop?

A.—In beginning the erection of side lever marine engines in the workshop, the first step is to level the bed plate lengthways and across, and strike a line up the centre, as near as possible in the middle, which indent with a chisel in various places, so that it may at any time be easily found again. Strike another line at right angles with this, either at the cylinder or crank centre, by drawing a perpendicular in the usual manner. Lay the other sole plate alongside at the right distance, and strike a line at the cylinder or crank centre of it also, shifting either sole plate a little endways until these two transverse lines come into the same line, which may be ascertained by applying a straight edge across the two sole plates. Strike the rest of the centres across, and drive a pin into each corner of each sole plate, which file down level, so as to serve for points of reference at any future stage; next, try the cylinder, or plumb it on the inside roughly, and see how it is for height, in order to ascertain whether much will be required to be chipped off the bottom, or whether more requires to be chipped off the one side than the other. Chip the cylinder bottom fair; set it in its place, plumb the cylinder very carefully with a straight edge and silk thread, and scribe it so as to bring the cylinder mouth to the right height, then chip the sole plate to suit that height. The cylinder must then be tried on again, and the parts filed wherever they bear hard, until the whole surface is well fitted. Next, chip the place for the framing; set up the framing, and scribe the horizontal part of the jaw with the scriber used for the bottom of the cylinder, the upright part being set to suit the shaft centres, and the angular flange of cylinder, where the stay is attached, having been previously chipped plumb and level. The stake wedges with which the framing is set up preparatorily to the operation of scribing, must be set so as to support equally the superincumbent weight, else the framing will spring from resting unequally, and it will be altogether impossible to fit it well. These directions obviously refer exclusively to the old description of side lever engine with cast iron framing; but there is more art in erecting an engine of that kind with accuracy, than in erecting one of the direct action engines, where it is chiefly turned or bored surfaces that have to be dealt with.

720. Q.—How do you lay out the positions of the centres of a side lever engine?

A.—In fixing the positions of the centres in side lever engines, it appears to be the most convenient way to begin with the main centre. The height of the centre of the cross head at half stroke above the plane of the main centre is fixed by the drawing of the engine, which gives the distance from the centre of cross head at half stroke to the flange of the cylinder; and from thence it is easy to find the perpendicular distance from the cylinder flange to the plane of the main centre, merely by putting a straight edge along level, from the position of the main centre to the cylinder, and measuring from the cylinder flauge down to it, raising or lowering the straight edge until it rests at the proper measurement. The main centre is in that plane, and the fore and aft position is to be found by plumbing up from the centre line on the sole plate. To find the paddle shaft centre, plumb up from the centre line marked on the edge of the sole plate, and on this line lay off from the plane of the main centre the length of the connecting rod, if that length be already fixed, or otherwise the height fixed in the drawing of the paddle shaft above the main centre. To fix the centre for the parallel motion shaft, when the parallel bars are connected with the cross head, lay off from the plane of main centre the length of the parallel bar from the centre of the cylinder, deduct the length of the radius crank, and plumb up the central line of motion shaft; lay off on this line, measuring from the plane of main centre, the length of the side rod; this gives the centre of parallel motion shaft when the radius bars join the cross head, as is the preferable practice where parallel motions are used. The length of the connecting rod is the distance from the centre of the beam when level, or the plane of the main centre, to the centre of the paddle shaft. The length of the side rods is the distance from the centre line of the beam when level, to the centre of the cross head when the piston is at half stroke. The length of the radius rods of the parallel motion is the distance from the point of attachment on the cross head or side rod, when the piston is at half stroke, to the extremity of the radius crank when the crank is horizontal; or in engines with the parallel motion attached to the cross head, it is the distance from the centre of the pin of the radius crank when horizontal to the centre of the cylinder. Having fixed the centre of the parallel motion shaft in the manner just described, it only remains to put the parts together when the motion is attached to the cross head; but when the motion is attached to the side rod, the end of the parallel bar must not move in a perpendicular line, but in an arc, the versed sine of which bears the same ratio to that of the side lever, that the distance from the top of the side rod to the point of attachment bears to the total length of the side rod.

721. Q.—How do you ascertain the accuracy of the parallel motion?

A.—The parallel motion when put in its place should be tested by raising and lowering the piston by means of the crane. First, set the beams level, and shift in or out the motion shaft plummer blocks or bearings, until the piston rod is upright. Then move the piston to the two extremes of its motion. If at both ends the cross head is thrown too much out, the stud in the beam to which the motion side rod is attached is too far out, and must be shifted nearer to the main centre; if at the extremities the cross head is thrown too far in, the stud in the beam is not out far enough. If the cross head be thrown in at the one end, and out equally at the other, the fault is in the motion side rod, which must be lengthened or shortened to remedy the defect.

722. Q.—Will you describe the method pursued in erecting oscillating engines?

A.—The columns here are of wrought iron, and in the case of small engines there is a template made of wood and sheet iron, in which the holes are set in the proper positions, by which the upper and lower frames are adjusted; but in the case of large engines, the holes are set off by means of trammels. The holes for the reception of the columns are cast in the frames, and are recessed out internally: the bosses encircling the holes are made quite level across, and made very true with a face plate, and the pillars which have been turned to a gauge are then inserted. The top frame is next put on, and must bear upon the collars of the columns so evenly, that one of the columns will not be bound by it harder than another. If this point be not attained, the surfaces must be further scraped, until a perfect fit is established. The whole of the bearings in the best oscillating engines are fitted by means of scraping, and on no other mode of fitting can the same reliance be placed for exactitude.

723. Q.—How do you set out the trunnions of oscillating engines, so that they shall be at right angles with the interior of the cylinder?

A.—Having bored the cylinder, faced the flange, and bored out the hole through which the boring bar passes, put a piece of wood across the mouth of the cylinder, and jam it in, and put a similar piece in the hole through the bottom of the cylinder. Mark the centre of the cylinder upon each of these pieces, and put into the bore of each trunnion an iron plate, with a small indentation in the middle to receive the centre of a lathe, and adjusting screws to bring the centre into any required position. The cylinder must then be set in a lathe, and hung by the centres of the trunnions, and a straight edge must be put across the cylinder mouth and levelled, so as to pass through the line in which the centre of the cylinder lies. Another similar straight edge, and similarly levelled, must be similarly placed across the cylinder bottom, so as to pass through the central line of the cylinder; and the cylinder is then to be turned round in the trunnion centres-the straight edges remaining stationary, which will at once show whether the trunnions are in the same horizontal plane as the centre of the cylinder, and if not, the screws of the plates in the trunnions must be adjusted until the central point of the cylinder just comes to the straight edge, whichever end of the cylinder is presented. To ascertain whether the trunnions stand in a transverse plane, parallel to the cylinder flange, it is only necessary to measure down from the flange to each trunnion centre; and if both these conditions are satisfied, the position of the centres may be supposed to be right. The trunnion bearings are then turned, and are fitted into blocks of wood, in which they run while the packing space is being turned out. Where many oscillating engines are made, a lathe with four centres is used, which makes the use of straight edges in setting out the trunnions superfluous.

724. Q.—Will you explain how the slide valve of a marine engine is set?

A.—Place the crank in the position corresponding to the end of the stroke, which can easily be done in the shop with a level, or plumb line; but in a steam vessel another method becomes necessary. Draw the transverse centre line, answering to the centre line of the crank shaft, on the sole plate of the engine, or on the cylinder mouth if the engine be of the direct action kind; describe a circle of the diameter of the crank pin upon the large eye of the crank, and mark off on either side of the transverse centre line a distance equal to the semi-diameter of the crank pin. From the point thus found, stretch a line to the edge of the circle described on the large eye of the crank, and bring round the crank shaft till the crank pin touches the stretched line; the crank may thus be set at either end of its stroke. When the crank is thus placed at the end of the stroke, the valve must be adjusted so as to have the amount of lead, or opening on the steam side, which it is intended to give at the beginning of the stroke; the eccentric must then be turned round upon the shaft until the notch in the eccentric rod comes opposite the pin on the valve lever, and falls into gear: mark upon the shaft the situation of the eccentric, and put on the catches in the usual way. The same process must be repeated for going astern, shifting round the eccentric to the opposite side of the shaft, until the rod again falls into gear. In setting valves, regard must of course be had to the kind of engine, the arrangements of the levers, and the kind of valve employed; and in any general instructions it is impossible to specify every modification in the procedure that circumstances may render advisable.

725. Q.—Is a similar method of setting the valve adopted when the link motion is employed.

A.—Each end of the link of the link motion has the kind of motion communicated to it that is due to the action of the particular eccentric with which that end is in connection. In that form of the link motion in which the link itself is moved up or down, there is a different amount of lead for each different position of the link, since to raise or lower the link is tantamount to turning the eccentric round on the shaft. In that form of the link motion in which the link itself is not raised or lowered, but is susceptible of a motion round a centre in the manner of a double ended lever, the lead continues uniform. In both forms of the link motion, as the stroke of the valve may be varied to any required extent while the lap is a constant quantity, the proportion of the lap relatively to the stroke of the valve may also be varied to any required extent, and the amount of the lap relatively with the stroke of the valve determines the amount of the expansion. In setting the valve when fitted with the link motion, the mode of procedure is much the same as when it is moved by a simple eccentric. The first thing is to determine if the eccentric rods are of the proper length, and this is done by setting the valve at half stroke and turning round the eccentric, marking each extremity of the travel of the end of the rod. The valve attachment should be midway between these extremes; and if it is not so, it must be made so by lengthening or shortening the rod. The forward and backward eccentric rods are to be adjusted in this way, and this being done, the engine is to be put to the end of the stroke, and the eccentric is to be turned round until the amount of lead has been given that is desired. The valve must be tried by turning the engine round to see that it is right at both centres, for going ahead and also for going astern. In some examples of the link motion, one of the eccentric rods is made a little longer than the other, and the position of the point of suspension or point of support powerfully influences the action of the link in certain cases, especially if the link and this point are not in the same vertical line. To reconcile all the conditions proper to the satisfactory operation of the valve in the construction of the link motion, is a problem requiring a good deal of attention and care for its satisfactory solution; and to make sure that this result is attained, the engine must be turned round a sufficient number of times to enable us to ascertain if the valve occupies the desired position, both at the top and bottom centres, whether the engine is going ahead or astern. This should also be tried with the starting handle in the different notches, or, in other words, with the sliding block in the slot or opening of the link in different positions.



MANAGEMENT OF MARINE BOILERS.

726. Q.—You have already stated that the formation of salt or scale in marine boilers is to be prevented by blowing out into the sea at frequent intervals a portion of the concentrated water. Will you now explain how the proper quantity of water to be blown out is determined?

A.—By means of the salinometer, which is an instrument for determining the density of the water, constructed on the principle of the hydrometer for telling the strength of spirits. Some of the water is drawn off from the boiler from time to time, and the salinometer is immersed in it after it has been cooled. By the graduations of the salinometer the saltness of this water is at once discovered; and if the saltness exceeds 8 ounces of salt in the gallon, more water should be blown out of the boiler to be replenished with fresher water from the sea, until the prescribed limit of freshness is attained. Should the salinometer be accidentally broken, a temporary one may be constructed of a phial weighted with a few grains of shot or other convenient weight. The weighted phial is first to be floated in fresh water, and its line of floatation marked; then to be floated in salt water, and its line of floatation marked; and another mark of an equal height above the salt water mark will be the blow off point.

727. Q.—HOW often should boilers be blown off in order to keep them free from incrustation?

A.—Flue boilers generally require to be blown off about twice every watch, or about twice in the four hours; but tubular boilers may require to be blown off once every twenty minutes, and such an amount of blowing off should in every case be adopted, as will effectually prevent any injurious amount of incrustation.

728. Q.—In the event of scale accumulating on the flues of a boiler, what is the best way of removing it?

A.—If the boilers require to be scaled, the best method of performing the operation appears to be the following:—Lay a train of shavings along the flues, open the safety valve to prevent the existence of any pressure within the boiler, and light the train of shavings, which, by expanding rapidly the metal of the flues, while the scale, from its imperfect conducting power, can only expand slowly, will crack off the scale; by washing down the flues with a hose, the scale will be carried to the bottom of the boiler, or issue, with the water, from the mud-hole doors. This method of scaling must be practised only by the engineer himself, and must not be intrusted to the firemen who, in their ignorance, might damage the boiler by overheating the plates. It is only where the incrustation upon the flues is considerable that this method of removing it need be practised; in partial cases the scale may be chipped off by a hatched faced hammer, and the flues may then be washed down with the hose in the manner before described.

729. Q.—Should the steam be let out of the boiler, after it has blown out the water, when the engine is stopped?

A.—No; it is better to retain the steam in the boiler, as the heat and moisture it occasions soften any scale adhering to the boiler, and cause it to peel off. Care must, however, be taken not to form a vacuum in the boiler; and the gauge cocks, if opened, will prevent this.

730. Q.—Are tubular boilers liable to the formation of scale in certain places, though generally free from it?

A.—In tubular boilers a good deal of care is required to prevent the ends of the tubes next the furnace from becoming coated with scale. Even when the boiler is tolerably clean in other places the scale will collect here; and in many cases where the amount of blowing off previously found to suffice for flue boilers has been adopted, an incrustation five eighths of an inch in thickness has formed in twelve months round the furnace ends of the tubes, and the stony husks enveloping them have actually grown together in some parts so as totally to exclude the water.

731. Q.—When a tubular boiler gets incrusted in the manner you have described, what is the best course to be adopted for the removal of the scale?

A.—When a boiler gets into this state the whole of the tubes must be pulled out, which may be done by a Spanish windlass combined with a pair of blocks; and three men, when thus provided, will be able to draw out from 50 to 70 tubes per day,—those tubes with the thickest and firmest incrustations being, of course, the most difficult to remove. The act of drawing out the tubes removes the incrustation; but the tubes should afterward be scraped by drawing them backward and forward between the old files, fixed in a vice, in the form of the letter V. The ends of the tube should then be heated and dressed with the hammer, and plunged while at a blood heat into a bed of sawdust to make them cool soft, so that they may be riveted again with facility. A few of the tubes will be so far damaged at the ends by the act of drawing them out, as to be too short for reinsertion: this result might be to a considerable extent obviated by setting the tube plates at different angles, so that the several horizontal rows of tubes would not be originally of the same length, and the damaged tubes of the long rows would serve to replace the short ones; but the practice would be attended with other inconveniences.

732. Q.—Is there no other means of keeping boilers free from scale than by blowing off?

A.—Muriatic acid, or muriate of ammonia, commonly called sal-ammoniac, introduced into a boiler, prevents scale to a great extent; but it is liable to corrode the boiler internally, and also to damage the engine, by being carried over with the steam; and the use of such intermixtures does not appear to be necessary, if blowing off from the surface of the water is largely practised. In old boilers, however, already incrusted with scale, the use of muriate of ammonia may sometimes be advantageous.

733. Q.—Are not the tubes of tubular boilers liable to be choked up by deposits of soot?

A.—The soot which collects in the inside of the tubes of tubular boilers is removed by means of a brush, like a large bottle brush; and the carbonaceous scale, which remains adhering to the interior of the tubes, is removed by a circular scraper. Ferules in the tubes interfere with the action of this scraper, and in the case of iron tubes ferules are now generally discarded; but it will sometimes be necessary to use ferules for iron tubes, where the tubes have been drawn and reinserted, as it may be difficult to refix the tubes without such an auxiliary. Tubes one tenth of an inch in thickness are too thin: one eighth of an inch is a better thickness, and such tubes will better dispense with the use of ferules, and will not so soon wear into holes.

734. Q.—If the furnace or flue of a boiler be injured, how do you proceed to repair it?

A.—If from any imperfection in the roof of a furnace or flue a patch requires to be put upon it, it will be better to let the patch be applied upon the upper, rather than upon the lower, surface of the plate; as if applied within the furnace a recess will be formed for the lodgment of deposit, which will prevent the rapid transmission of the heat in that part; and the iron will be very liable to be again burned away. A crack in a plate may be closed by boring holes in the direction of the crack, and inserting rivets with large heads, so as to cover up the imperfection. If the top of the furnace be bent down, from the boiler having been accidentally allowed to get short of water, it may be set up again by a screw jack,—a fire of wood having been previously made beneath the injured plate; but it will in general be nearly as expeditious a course to remove the plate and introduce a new one, and the result will be more satisfactory.

735. Q.—In the case of the chimney being carried away by shot or otherwise, what course would you pursue?

A.—In some cases of collision, the funnel is carried away and lost overboard, and such cases are among the most difficult for which a remedy can be sought. If flame come out of the chimney when the funnel is knocked away, so as to incur the risk of setting the ship on fire, the uptake of the boiler must be covered over with an iron plate, or be sufficiently covered to prevent such injury. A temporary chimney must then be made of such materials as are on board the ship. If there are bricks and clay or lime on board, a square chimney may be built with them, or, if there be sheet iron plates on board, a square chimney may be constructed of them. In the absence of such materials, the awning stanchions may be set up round the chimney, and chain rove in through among them in the manner of wicker work, so as to make an iron wicker chimney, which may then be plastered outside with wet ashes mixed with clay, flour, or any other material that will give the ashes cohesion. War steamers should carry short spare funnels, which may easily be set up should the original funnel be shot away; and if a jet of steam be let into the chimney, a very short and small funnel will suffice for the purpose of draught.



MANAGEMENT OF MARINE ENGINES.

736. Q.—What are the most important of the points which suggest themselves to you in connection with the management of marine engines?

A.—The attendants upon engines should prepare themselves for any casualty that may arise, by considering possible cases of derangement, and deciding In what way they would act should certain accidents occur. The course to be pursued must have reference to particular engines, and no general rules can therefore be given; but every marine engineer should be prepared with the measures to be pursued in the emergencies in which he may be called upon to act, and where everything may depend upon his energy and decision.

737. Q.—What is the first point of a marine engineer's duty?

A.—The safe custody of the boiler. He must see that the feed is maintained, being neither too high nor too low, and that blowing out the supersalted water is practised sufficiently. The saltness of the water at every half hour should be entered in the log book, together with the pressure of steam, number of revolutions of the engine, and any other particulars which have to be recorded. The economical use of the fuel is another matter which should receive particular attention. If the coal is very small, it should be wetted before being put on the fire. Next to the safety of the boiler, the bearings of the engine are the most important consideration. These points, indeed, constitute the main parts of the duty of an engineer, supposing no accident to the machinery to have taken place.

738. Q.—If the eccentric catches or hoops were disabled, how would you work the valve?

A.—If the eccentric catches or hoops break or come off, and the damage cannot readily be repaired, the valve may be worked by attaching the end of the starting handle to any convenient part of the other engine, or to some part in connection with the connecting rod of the same engine. In side lever engines, with the starting bar hanging from the top of the diagonal stay, as is a very common arrangement, the valve might be wrought by leading a rope from the side lever of the other engine through blocks so as to give a horizontal pull to the hanging starting bar, and the bar could be brought back by a weight. Another plan would be, to lash a piece of wood to the cross tail butt of the damaged engine, so as to obtain a sufficient throw for working the valve, and then to lead a piece of wood or iron, from a suitable point in the piece of wood attached to the cross tail, to the starting handle, whereby the valve would receive its proper motion. In oscillating engines it is easy to give the required motion to the valve, by deriving it from the oscillation of the cylinder.

739. Q.—What would you do if a crank pin broke?

A.—If the crank pin breaks in a paddle vessel with two engines, the other engine must be made to work one wheel. In a screw vessel the same course may be pursued, provided the broken crank is not the one through which the force of the other engine is communicated to the screw. In such a case the vessel will be as much disabled as if she broke the screw shaft or screw.

740. Q.—Will the unbroken engine, in the case of disarrangement of one of the two engines of a screw or paddle vessel, be able of itself to turn the centre?

A.—It will sometimes happen, when there is much lead upon the slide valve, that the single engine, on being started, cannot be got to turn the centre if there be a strong opposing wind and sea; the piston going up to near the end of the stroke, and then coming down again without the crank being able to turn the centre. In such cases, it will be necessary to turn the vessel's head sufficiently from the wind to enable some sail to be set; and if once there is weigh got upon the vessel the engine will begin to work properly, and will continue to do so though the vessel be put head to wind as before.

741. Q.—What should be done if a crack shows itself in any of the shafts or cranks?

A.—If the shafts or cranks crack, the engine may nevertheless be worked with moderate pressure to bring the vessel into port; but if the crack be very bad, it will be expedient to fit strong blocks of wood under the ends of the side levers, or other suitable part, to prevent the cylinder bottom or cover from being knocked out, should the damaged part give way. The same remark is applicable when flaws are discovered in any of the main parts of the engine, whether they be malleable or cast iron; but they must be carefully watched, so that the engines may be stopped if the crack is extending further. Should fracture occur, the first thing obviously to be done is to throw the engines out of gear; and should there be much weigh on the vessel, the steam should at once be thrown on the reverse side of the piston, so as to counteract the pressure of the paddle wheel.

742. Q.—Have you any information to offer relative to the lubrication of engine bearings?

A.—A very useful species of oil cup is now employed in a number of steam vessels, and which, it is said, accomplishes a considerable saving of oil, at the same time that it more effectually lubricates the bearings. A ratchet wheel is fixed upon a little shaft which passes through the side of the oil cup, and is put into slow revolution by a pendulum attached to its outside and in revolving it lifts up little buckets of oil and empties them down a funnel upon the centre of the bearing. Instead of buckets a few short pieces of wire are sometimes hung on the internal revolving wheel, the drops of oil which adhere on rising from the liquid being deposited. upon a high part set upon the funnel, and which, in their revolution, the hanging wires touch. By this plan, however, the oil is not well supplied at slow speeds, as the drops fall before the wires are in proper position for feeding the journal. Another lubricator consists of a cock or plug inserted in the neck of the oil cup, and set in revolution by a pendulum and ratchet wheel, or any other means. There is a small cavity in one side of the plug, which is filled with oil when that side is uppermost, and delivers the oil through the bottom pipe when it comes opposite to it.

743. Q.—What are the prevailing causes of the heating of bearings?

A.—Bad fitting, deficient surface, and too tight screwing down. Sometimes the oil hole will choke, or the syphon wick for conducting the oil from the oil cup into the central pipe leading to the bearing will become clogged with mucilage from the oil. In some cases bearings heat from the existence of a cruciform groove on the top brass for the distribution of the oil, the effect of which is to leave the top of the bearings dry. In the case of revolving journals the plan for cutting a cruciform channel for the distribution of the oil does not do much damage; but in other cases, as in beam journals, for instance, it is most injurious, and the brasses cannot wear well wherever the plan is pursued. The right way is to make a horizontal groove along the brass where it meets the upper surface of the bearing, so that the oil may be all deposited on the highest point of the journal, leaving the force of gravity to send it downward. This channel should, of course, stop short a small distance from each flange of the brass, otherwise the oil would run out at the ends.

744. Q.—If a bearing heats, what is to be done?

A.—The first thing is to relax the screws, slow or stop the engine, and cool the bearing with water, and if it is very hot, then hot water may be first employed to cool it, and then cold. Oil with sulphur intermingled is then to be administered, and as the parts cool down, the screws may be again cautiously tightened, so as to take any jump off the engine from the bearing being too slack. The bearings of direct acting screw engines require constant watching, as, if there be any disposition to heat manifested by them, they will probably heat with great rapidity from the high velocity at which the engines work. Every bearing of a direct acting screw engine should have a cock of water laid on to it, which may be immediately opened wide should heating occur; and it is advisable to work the engine constantly, partly with water, and partly with oil applied to the bearings. The water and oil are mixed by the friction into a species of soap which both cools and lubricates, and less oil moreover is used than if water were not employed. It is proper to turn off the water some time before the engine is stopped, so as to prevent the rusting of the bearings.



MANAGEMENT OF LOCOMOTIVES.

745. Q.—What are the chief duties of the engine driver of a locomotive?

A.—His first duties are those which concern the safety of the train; his next those which concern the safety and right management of the engine and

boiler. The engine driver's first solicitude should be relative to the observation and right interpretation of the signals; and it is only after these demands upon his attention have been satisfied, that he can look to the state of his engine.

746. Q.—As regards the engine and boiler, what should his main duties be?

A.—The engineer of a locomotive should constantly be upon the foot board of the engine, so that the regulator, the whistle or the reversing handle may be used instantly, if necessary; he must see that the level of the water in the boiler is duly maintained, and that the steam is kept at a uniform pressure. In feeding the boilers with water, and the furnaces with fuel, a good deal of care and some tact are necessary, as irregularity in the production of steam will often occasion priming, even though the water be maintained at a uniform level; and an excess of water will of itself occasion priming, while a deficiency is a source of obvious danger. The engine is generally furnished with three gauge cocks, and water should always come out of the second gauge cock, and steam out of the top one when the engine is running: but when the engine is at rest, the water in the boiler is lower than when in motion, so that when the engine is at rest, the water will be high enough if it just reaches to the middle gauge cock. In all boilers which generate steam rapidly, the volume of the water is increased by the mingled steam, and in feeding with cold water the level at first falls; but it rises on opening the safety valve, which causes the steam in the water to swell to a larger volume. In locomotive boilers, the rise of the water level due to the rapid generation of steam is termed "false water." To economize fuel, the variable expansion gear, if the engine has one, should be adjusted to the load, and the blast pipe should be worked with the least possible contraction; and at stations the damper should be closed to prevent the dissipation of heat.

747. Q.—In starting from a station, what precautions should be observed with respect to the feed?

A.—In starting from a station, and also in ascending inclined planes, the feed water is generally shut off; and therefore before stopping or ascending inclined planes, the boiler should be well filled up with water. In descending inclined planes an extra supply of water may be introduced into the boiler, and the fire may be fed, as there, is at such times a superfluity of steam. In descending inclined planes the regulator must be partially closed, and it should be entirely closed if the plane be very steep. The same precaution should be observed in the case of curves, or rough places on the line, and in passing over points or crossings.

748. Q.—In approaching a station, how should the supply of water and fuel be regulated?

A.—The boiler should be well filled with water on approaching a station, as there is then steam to spare, and additional water cannot be conveniently supplied when the engine is stationary. The furnace should be fed with small quantities of fuel at a time, and the feed should be turned off just before a fresh supply of fuel is introduced. The regulator may, at the same time, be partially closed; and if the blast pipe be a variable one, it will be expedient to open it widely while the fuel is being introduced, to check the rush of air in through the furnace door, and then to contract it very much so soon as the furnace door is closed, in order to recover the fire quickly. The proper thickness of coke upon the grate depends upon the intensity of the draught; but in heavily loaded engines it is usually kept up to the bottom of the fire door. Care, however, must be taken that the coke does not reach up to the bottom row of tubes so as to choke them up. The fuel is usually disposed on the grate like a vault; and if the fire box be a square one, it is heaped high in the corners, the better to maintain the combustion.

749. Q.—How can you tell whether the feed pumps are operating properly?

A.—To ascertain whether the pumps are acting well, the pet cock must be turned, and if any of the valves stick they will sometimes be induced to act again by working with the pet cock open, or alternately open and shut. Should the defect arise from a leakage of steam into the pump, which prevents the pump from drawing, the pet cock remedies the evil by permitting the steam to escape.

750. Q.—What precautions should be taken against priming in locomotives?

A.—Should priming occur from the water in the boiler being dirty, a portion of it may be blown out; and should there be much boiling down through the glass gauge tube, the stop cock may be partially closed. The water should be wholly blown out of locomotive boilers three times a week, and at those times two mud-hole doors at opposite corners of the boiler should be opened, and the boiler be washed internally by means of a hose. If the boiler be habitually fed with dirty water, the priming will be a constant source of trouble.

751. Q.—What measures should the locomotive engineer take, to check the velocity of the train, on approaching a station where he has to stop?

A.—On approaching a station the regulator should be gradually closed, and it should be completely shut about half a mile from the station if the train be a very heavy one: the train may then be brought to rest by means of the breaks. Too much reliance, however, must not be put upon the breaks, as they sometimes give way, and in frosty weather are nearly inoperative. In cases of urgency the steam may be thrown upon the reverse side of the piston, but it is desirable to obviate this necessity as far as possible. At terminal stations the steam should be shut off earlier than at roadside stations, as a collision will take place at terminal stations if the train overshoots the place where it ought to stop. There should always be a good supply of water when the engine stops, but the fire may be suffered gradually to burn low toward the conclusion of the journey.

752. Q.—What is the duty of an engine man on arriving at the end of his journey?

A.—So soon as the engine stops it should be wiped down, and be then carefully examined: the brasses should be tried, to see whether they are slack or have been heating; and, by the application of a gauge, it should be ascertained occasionally whether the wheels are square on their axles, and whether the axles have end play, which should be prevented. The stuffing boxes must be tightened, and the valve gear examined, and the eccentrics be occasionally looked at to see that they have not shifted on their axles, though this defect will be generally intimated by the irregular beating of the engines. The tubes should also be examined and cleaned out, and the ashes emptied out of the smoke box through the small ash door at the end. If the engine be a six-wheeled one, with the driving wheels in the middle, it will be liable to pitch, and oscillate if too much weight be thrown upon the driving wheels; and where such faults are found to exist, the weight upon the drivings wheels should be diminished. The practice of blowing off the boiler by the steam, as is always done in marine boilers, should not be permitted as a general rule in locomotive boilers, when the tubes are of brass and the fire box of copper; but when the tubes and fire boxes are of iron, there will not be an equal risk of injury. Before starting on a journey, the engine man should take a summary glance beneath the engine—but before doing so he ought to assure himself that no other engine is coming up at the time. The regulator, when the engine is standing, should be closed and locked, and the eccentric rod be fixed out of gear, and the tender break screwed down; the cocks of the oil vessels should at the same time be shut, but should all be opened a short time before the train starts.

753. Q.—What should be done if a tube bursts in the boiler?

A.—When a tube bursts, a wooden or iron plug must be driven into each end of it, and if the water or steam be rushing out so fiercely that the exact position of the imperfection cannot be discovered, it will be advisable to diminish the pressure by increasing the supply of feed water. Should the leak be so great that the level of the water in the boiler cannot be maintained, it will be expedient to drop the bars and quench the fire, so as to preserve the tubes and fire box from injury.

754. Q.—If any of the working parts of a locomotive break or become deranged, what should be done?

A.—Should the piston rod or connecting rod break, or the cutters fall out or be clipped off—as sometimes happens to the piston cutter when the engine is suddenly reversed upon a heavy train—the parts should be disconnected, if the connection cannot be restored, so as to enable one engine to work; and of course the valve of the faulty engine must be kept closed. If one engine has not power enough to enable the train to proceed with the blast pipe full open, the engine may perhaps be able to take on a part of the carriages, or it may run on by itself to fetch assistance. The same course must be pursued if any of the valve gearing becomes deranged, and the defects cannot be rectified upon the spot.

755. Q.—What are the most usual causes of railway collisions?

A.—Probably fogs and inexactness in the time kept by the trains. Collisions have sometimes occurred from carriages having been blown from a siding on to the rails by a high wind; and the slippery state of the rails, or the fracture of a break, has sometimes occasioned collisions at terminal stations. Collision has also repeatedly taken place from one engine having overtaken another, from the failure of a tube in the first engine, or from some other slight disarrangement; and collision has also taken place from the switches having been accidentally so left as to direct the train into a siding, instead of continuing it on the main line. Every train now carries fog signals, which are detonating packets, which are fixed upon the rails in advance or in the rear of a train which, whether from getting off the rails or otherwise, is stopped upon the line, and which are exploded by the wheels of any approaching train.

756. Q.—What other duties of an engine-driver are there deserving attention?

A.—They are too various to be all enumerated here, and they also vary somewhat with the nature of the service. One rule, however, of universal application, is for the driver to look after matters himself, and not delegate to the stoker the duties which the person in charge of the engine should properly perform. Before leaving a station, the engine-driver should assure himself that he has the requisite supply of coke and water. Besides the firing tools and rakes for clearing the tubes, he should have with him in the tender a set of signal lamps and, torches, for tunnels and for night, detonating signals, screw keys, a small tank of oil, a small cask of tallow, and a small box of waste, a coal hammer, a chipping hammer, some wooden and iron plugs for the tubes, and an iron tube holder for inserting them, one or two buckets, a screw jack, wooden and iron wedges, split wire for pins, spare cutters, some chisels and files, a pinch bar, oil cans and an oil syringe, a chain, some spare bolts, and some cord, spun yarn, and rope.



INDEX.

Accidents in steam vessels, proper preparation for. Admiralty rule for horse power. Adhesion of wheels of locomotives to rails. Air, velocity of, entering a vacuum, required for combustion of coal; law of expansion of, by heat; Air pump, description of, action of; proper dimensions of. Air pump of marine engines, details of. Air pump of oscillating engine. Air pump of direct acting screw engines. Air pumps made both single and double acting, difference of, explained. Air pumps, double acting valves of, bad vacuum in; causes and remedy. Air pump rods, brass or copper, in marine engines. Air pump bucket, valves of. Air pump, connecting rod and cross head of oscillating engine. Air pump rod of oscillating engine. Air pump arm. Air vessels applied to suction side of pumps. "Alma," engine of, by Messrs. John Bourne & Co. "Amphion," engines of. Amoskeag steam fire engine. Angle iron in boilers, precautions respecting. Apparatus for raising screw propeller. Atmospheric valve. Atmospheric resistance to railway trains. Auxiliary power, screw vessels with. Axle bearings of locomotives. Axle guards. Axles and wheels of modern locomotives. "Azof," slide valve of.

Babbitt's metal, how to compound. Balance piston to take pressure off slide valve. Ball valves. Barrel of boiler of modern locomotives. Beam, working of land engine, main or working strength proper for. Bearings of engines or other machinery, rule for determining proper surface of. Bearings, heating of, how to prevent or remedy, journals should always bottom, as, if they grip on the sides, the pressure is infinite. Beattie's screw. Belidor's valves might be used for foot and delivery valves. Bell-metal, composition of. Blast pipe of locomotives, description of. Blast in locomotives, exhaustion produced by, proper construction of the blast pipe; the blast pipe should be set below the root of the chimney so much that the cone of escaping steam shall just fill the chimney. Blast pipe with variable orifice, at one time much used. Blow-off cock of locomotives. Blow-off cocks of marine boilers, proper construction of. Blow-off cocks, description of. Blowing off supersalted water from marine boilers. Blowing off, estimate of heat lost by, mode of. Blow through valve, description of. Blowing furnaces, power necessary for. Bodies, falling, laws of. Bodmer, expansion valve by. Boilers, general description of: the wagon boiler, the Cornish boiler; the marine flue boiler; the marine tubular boiler; locomotive boiler—see Locomotives. Boilers proportions of: heating surface of, fire grate, surface of; consumption of fuel on each square foot of fire bars in wagon, Cornish, and locomotive boilers; calorimmeter and vent of boilers; comparison of proportions of wagon, flue, and tubular boilers; evaporative power of boilers; power generated by evaporation of a cubic foot of water; proper proportions of modern marine boilers both flue and tubular; modern locomotive boilers; exhaustion produced by blast in locomotives; increased evaporation from increased exhaustion; strength of boilers; experiments on, by Franklin Institute; by Mr. Fairbairn; mode of computing strength of boilers; staying of. Boilers, marine, prevented from salting by blowing off, early locomotive and contemporaneous marine boilers compared; chimneys of land; rules for proportions of chimneys; chimneys of marine boilers. Boilers, constructive details of: riveting and caulking of land boilers, proving of; seams payed with mixture of whiting and linseed oil; setting of wagon boilers; riveting of marine boilers; precautions respecting angle iron; how to punch the rivet holes and shear edges of plates; setting of marine boilers in wooden vessels; mastic cement for setting marine boilers; composition of mastic cement; best length of furnace; configuration of furnace bars; advantages and construction of furnace bridges; various forms of dampers; precautions against injury to boilers from intense heat; tubing of boilers; proper mode of staying tube plates; proper mode of constructing steamboat chimneys; waste steam-pipe and funnel casing; telescope chimneys; formation of scale in marine boilers; injury of such incrustations; amount of salt in sea water; saltness permissible in boilers; amount of heat lost by blowing off; mode of discharging the supersalted water; Lamb's scale preventer; internal corrosion of marine boilers; causes of internal corrosion; surcharged steam produced from salt water; stop valves between boilers; safety or escape valve on feed pipe; locomotive boilers consist of the fire box, barrel for holding tubes, and smoke box; dimensions of the barrel and thickness of plates; mode of staying fire box and furnace crown; fire bars, ash box, and chimney; steam dome used only in old engines; manhole, mudholes, and blow-oft cock; tube plate, and mode of securing tubes; expanding mandrels; various forms of regulator. Boilers of modern locomotives. Boiler, the, proper care of, the first duty of the engineer. Bolts, proper proportions of. Boring of cylinders. Boulton and Watt's rules for fly wheel, proportions of marine flue boilers; rule for proportions of chimneys of land boilers; of marine boilers; experiments on the resistance of vessels in water. Bourdon's steam and vacuum gauges. Bourne, expansion valves by. Bourne, Messrs. J. & Co., direct acting screw engines by. Brass for bearings, composition of. Brazing solders. Bridges in furnaces, benefits of. Burning of boilers, precautions against. Bursting velocity of fly wheel, and of railway wheels. Bursting of boilers, causes of; precautions against; may be caused by accumulations of salt. Butterfly valves of air pump.

Cabrey, expansion valve by. Calorimeter of boilers, definition of. Cams, proper forms of. Cast iron, strength of, proportions of cast iron beams; effects of different kinds of strains on beams; strength to resist shocks not proportional to strength to resist strains; to attain maximum strength should be combined with wrought iron. Casting of cylinders. Case-hardening, how to accomplish. Cataract, explanation of nature and uses of. Caulking of land boilers. Cement, mastic, for setting marine boilers. Central forces. Centre of pressure of paddle wheels. Centres of gravity, gyration and oscillation. Centres for fixing arms of paddle wheel. Centres of an engine, how to lay off. Centrifugal force, nature of, rule for determining; bursting velocity of fly wheel; and of railway wheels. Centrifugal pump will supersede common pump. Centripetal force, nature of. Chimney of locomotives. Chimney of steam vessels, what to do if carried away. Chimneys of land boilers, Boulton and Watt's rule for proportions of; of marine boilers. Chimneys, exhaustion produced by, high and wide chimneys in locomotives injurious. Chimneys of steamboats, telescope. Clark's patent steam fire regulator. Coal, constituents of, combustion of air required for; evaporative efficacy of; of wood, turf, and coke. Cocks, proper construction of. Cog wheels for screw engines. Coke, evaporative efficacy of. Cold water pump, description of, rule for size of. Combustion, nature of. Combustion of coal, air required for. Combustion, slow and rapid, comparative merits of, rapid combustion necessary in steam vessels, and enables less heating, surface in the boiler to suffice. Conchoidal propeller. Condensation of steam, water required for. Condenser, description of, action of; proper dimensions of. Condenser of oscillating engine. Condenser of direct acting screw engine. Condensing engine, definition of. Condensing water, how to provide when deficient. Conical pendulum or governor. Connecting rod, description of, strength proper for. Connecting rod of direct acting screw engines, of locomotives. Consumption of fuel on each square foot of fire bars in wagon, Cornish, and locomotive boilers. Copper, strength of. Corliss's steam engine. Corrosion produced by surcharged steam. Corrosion of marine boilers, causes of. Cost of locomotives. Cotton spinning, power necessary for. Counter for counting strokes of an engine. Crank, description of, unequal leverage of, corrected by fly wheel; no power lost by; action of; strength proper for. Crank of direct acting screw engines. Crank pin, strength proper for. Crank pin of direct acting screw engines. Cranked axle of locomotives. Cross head, description of, strength proper for. Cross head of direct acting screw engines. Cross tail, description of. Cylinder, description of, strength proper for. Cylinder of oscillating engine, of direct acting screw engine. Cylinders should have a steam jacket, and be felted and planted, should have escape valves. Cylinders of locomotives should be large, proper arrangement of. Cylinders, how to cast, how to bore; how to grind. Cylinder jacket, advantages of.

Damper. Dampers, various forms of. Deadwood, hole in, for screw. Delivery valve, description of. Delivery or discharge valves, proper dimensions of. Delivery valves might be made on Belidor's plan. Delivery valves in mouth of air pump, of india rubber. Direct acting screw engines should be balanced. Direct acting screw engine by Messrs. John Bourne &, Co., cylinder; discs; guides; screw shaft brasses; air pump; slide valve; balance piston; connecting rod; piston rods; cross head; air pump arm; feed pump; crank pin; screw shaft; thrust plummer block; link motion; screw propeller. Discharge valves. Disc valves of india rubber for air pumps. Discs of direct acting screw engine instead of crank. Dodds, expansion valve by. Double acting engines, definition of. Double acting air pumps, valves of; faults of. Draw bolt. Dredging earth out of rivers, power necessary for. Driving wheels of locomotives. Driving piles, power necessary for. Duplex pump, Worthington's. Dundonald, Earl of, screw by. Duty of engines and boilers, how the duty is ascertainable. Dynamometer, description of. Dynamometric power of screw vessels.

Eccentric, description of, sometimes made loose for backing. Eccentric and eccentric rod of oscillating engine. Eccentric notch should be fitted with a brass bush. Eccentric straps of locomotives, rods of locomotives. Eccentrics of locomotives, how to readjust. Economy of fuel in steam vessels. Edwards, expansion valve by. Elasticity, limits of. Engine, high pressure, definition of, low pressure, definition of. Engines, classification of, rotative, definition of; rotatory, definition of; single acting, definition of; double acting, definition of; mode of erecting in a vessel; how to refix if they have become loose. Engineers of steam vessels should make proper preparation for accidents. Equilibrium slide valve, grid-iron valve. Erecting engines in a vessel. Erection of engines in the workshop. Escape valve on feed pipe. Escape valves for letting water out of cylinders. Evaporative efficacy of coal, of wood, turf, and coke. Evaporative power of boilers, power generated by evaporation of a cubic foot of water; increase of evaporation due to increased exhaustion in locomotives. Excavator, Otis's. Exhaustion produced by chimneys, by the blast in locomotives; increased evaporation from increased exhaustion. Expanding mandrels for tubing boilers. Expansion of air by heat. Expansion of surcharged steam by heat. Expansion of steam, pressure of steam inversely as the space occupied; law of expansion; rule for computing the increase of efficiency produced by working expansively; necessity of efficient provisions against refrigeration in working expansively; advantages of steam jacket; Forms of apparatus for working expansively: lap on the slide valve wire drawing the steam; Cornish expansion valve, in rotative engines worked by a cam; mode of varying the degree of expansion; proper forms of cams; the link motion; expansion valves, by Cabrey, Fenton, Dodds, Farcot, Edwards, Lavagrian, Bodmer, Meyer, Hawthorn, Gonzenbach, and Bourne. Expansion joint in valve casing. Expansion valves, Cornish, the link motion; by Cabrey, Fenton, Dodds, Farcot, Edwards, Lavagrian, Bodmer, Meyer, Hawthorn, Gouzenbach, and Bourne. Explosions of boilers, causes of explosions; precautions against; dangers of accumulations of salt.

Face plates or planometers. Falling bodies, laws of. Farcot, expansion valve by. Feathering paddle wheels, description of, details of. Feed pump, description of, action of; proper dimensions of; rule for proportioning. Feed pump plunger, and valves. Feed pumps of locomotives, details of. Feed pumps of direct acting screw engines. Fenton, expansion valve by. Fire bars of locomotives. Fire box of locomotives, mode of staying. Fire box of modern locomotives. Fire engines, cost of running. Fire grate surface of boilers. Fire grate in locomotives should be of small area, coke proper to be burned per hour on each square foot of bars. Firing furnaces, proper mode of. Flaws in valves or cylinders, how to remedy. Float for regulating water level in boilers. Floats of paddle. Floats of paddle wheels, increased resistance of, if oblique, floats should be large. Fly wheel corrects unequal leverage of crank, proper energy for; Boulton and Watt's rule for; bursting velocity of; description of; action of, in redressing irregularities of motion. Foot valve, description of, proper dimensions of. Foot valves might be made on Belidor's plan, of india rubber. Frame at stern for holding screw propeller. Framing of locomotives. Framing of oscillating engine. Franklin Institute, experiments on steam by. French Academy, experiments on steam by. Friction, nature of, does not vary as the rubbing surfaces, but as the retaining pressure; does not increase with the velocity per unit of distance, but increases with the velocity per unit of time; measures of friction; effect of unguents; kind of unguent should vary with the pressure; Morin's experiments; rule for determining proper surfaces of bearings; friction of rough surfaces. Friction of the water the main cause of the resistance of vessels of good shape. Fuel burnt on each square foot of fire bars in wagon, Cornish, and locomotive boilers, economy of, in steam vessels. Funnel casing. Funnel, what to do if carried away. Funnels of steam boats. See Chimneys. Furnaces, proper mode of firing, smoke burning: Williams's argand; Prideaux's; Boulton and Watt's dead plate; revolving crate; Juckes's; Maudslay's; Hull's, Coupland's, Godson's, Robinson's, Stevens's, Hazeldine's, &c.. Furnaces of marine boilers, proper length of. Furnace bridges, benefits of. Fusible metal plugs useless as antidotes to explosions.

Gauges, vacuum, steam; gauge cocks and glass tubes for showing level of water in boiler, description of. Gauge cocks for showing level of water in boiler. Gearing for screw engines. Gibs and cutters, strengths proper for. Giffard's injector. Glass tubes for showing water level in boilers. Glass tube cocks. Gonzeubach, expansion valve by. Gooch's indicator. Gooch's locomotive. Governor or conical pendulum, description of. Governor, Porter's patent. Gravity, centre of. "Great Western," boilers of, by Messrs. Maudslay. Gridiron valve. Griffith's screw. Grinding corn, power necessary for. Grinding of cylinders. Gudgeons, strength proper for. Guides of locomotives. Guides of direct acting screw engine. Gun metal, strength of. Gyration, centre of.

Harvey and West's pump valves. Hawthorn, expansion valve by. Heat, latent, definition of. Heat, specific, definition of. Heat, Regnault's experiments on. Heat, loss of, by blowing off marine boilers. Heating surface of boilers. Heating surface per square foot of fire bars in locomotives, a cubic foot of water evaporates by five square feet of heating surface. Heating of bearings, causes of, bearings should always be slack at the sides, else the pressure is infinite. High pressure engine, definition of. High pressure engines, power of. High speed engines, arrangements proper for high speeds. Hoadley's portable engine. Hodgson's screw. Hoe & Co.'s steam engine. Holding down bolts of marine engines, or bolts for securing engines to hull. Holms's screw propeller. Horses power, definition of, nominal horse power; actual power ascertained by the indictator; Admiralty rule for. Hot water or feed pump, description of. Hot well, description of.

Increasing pitch of screw. Incrustation in boilers. See also Salt. India rubber valves for air pump. Indicator, description of the, by McNaught, structure and mode of using; Gooch's continuous indicator. Injection cock. Injection cocks of marine engines at ship's sides. Injection orifice, proper area of. Injector, Giffard's. Injection valve. Inside cylinder locomotives. Iron, strength of, limits of elasticity of; proper strain to be put upon iron in engines and machines; aggravation of strain by being intermittent; increase of strain due to deflection; strength of pillars and tubes, combination of malleable and cast iron. Iron, cast, strength of, cast iron beams; may be strong to resist strains, but not strong to resist shocks; should be combined with wrought iron to obtain maximum strength. Iron, if to be case hardened, should be homogeneous.

Jacket of cylinder, advantages of. Joints, rust, how to make.

Kingston's valves.

Lamb's scale preventer. Lantern brass in stuffing boxes. Lap and lead of the valve, meaning of. Large vessels have least proportionate resistance. Latent heat, definition of. Latta's steam fire engine. Lavagrian, expansion valve by. Lead and lap of the valve, meaning of. Lead of the valve, benefits of. Lever, futility of plans for deriving power from a lever. Lifting apparatus for screw propeller. Limits of elasticity. Links, main description of.

Link motion of direct acting screw engine. Link motion, how to set. Locomotive engines, general description of the locomotive; Stephenson's locomotive; Gooch's locomotive for the wide gauge; Crampton's locomotive for the narrow gauge. Locomotives, adhesion of wheels of, cost and performance of; framing of; cylinders of; springs of; outside and inside cylinders; sinuous motion of; rocking motion of; pitching motion of; pistons; piston rods; guides; cranked axle; axle bearings; eccentrics; eccentric rod; starting handle; link motion; valves, how to set; eccentrics, how to readjust; feed pumps; connection of engine and tender, driving wheels; wheel tires. Locomotive engine of modern construction, example of, fire box; barrel of boiler; tubes; tube plate; framing; axle guards; draw bolt; wheels and axles; cylinders; valve; piston; piston rod; guides; connecting rod; eccentrics; link motion; regulator; blast pipe; safety valve; feed pump; tendencies of improvement in locomotives. Locomotives, management of. Locomotive boilers, examples of modern proportions. Locomotive boilers, details of. Low pressure or condensing engine, definition of. Lubrication of rubbing surfaces, the friction depends mainly on the nature of lubricant; oil forced out of bearings, if the pressure exceeds 800 lbs. per square inch longitudinal section; water a good lubricant if the surfaces are large enough. Lubrication of engine bearings.

McNaught's indicator. Main beam, strength proper for. Main centre, description of, strength proper for. Main links, description of, strength proper for. Mandrels, expanding, for tubing boilers. Manhole door. Manhole of locomotives. Marine flue boilers, proportions of. See also Boilers. Marine boilers of modern construction, proper proportions of. Marine engines. See Steam Engines, marine. Mastic cement for setting marine boilers. Maudslay, Messrs., boilers of "Retribution" and "Great Western," by, Mechanical powers, misconceptions respecting. Mechanical power, definition of, indestructible and eternal; the sun the source of mechanical power. Metallic packing for pistons. Metallic packing for stuffing boxes. Meyer, expansion valve by. Miller, Ravenhill & Co.'s mode of fixing piston rod to piston. Modern locomotives. Momentum, or vis viva. Morin, experiments on friction by. Mudholes of locomotives. Muntz's metal, composition of.

"Niger" and "Basilisk," trials of. "Nile," boilers of the, by Boulton and Watt. Notch of eccentric should be fitted with brass bush.

Oils for lubrication. See Lubrication. Oscillation, centre of. Oscillating paddle engine, description of. Oscillating engine, advantages of, futility of objections to; details of cylinder; framing; condenser; air pump; trunnions; valve and valve casing; piston; piston rod; air pump connecting rod and cross head; air pump rod; eccentric and eccentric rod; valve gear; valve sector; shaft plummer blocks; trunnion plummer blocks; feathering paddle wheels; packing of trunnions. Oscillating engines, how to erect. Otis's excavator. Outside and inside cylinder locomotives.

Packing for stuffing box of Watt's engine. Packing of piston of pumping engines, how to accomplish. Packing of trunnions. Paddle bolts, proper mode of forming. Paddle centres. Paddle floats. Paddle shaft, description of. Paddle shaft, details of. Paddle shaft plummer blocks of oscillating engines. Paddle wheels, details of, structure and operation of; slip of; centre of pressure of; rolling circle; action of oblique floats; rule for proportioning paddle wheels; benefits of large floats. Paddle wheels, feathering, description of; details of. Paddles and screw combined. Parallel motion, description of, how to lay off centres of. Pendulum, cause of vibrations of; relation of vibrations of pendulum to velocity of falling bodies; conical pendulum or governor. Penn, Messrs., engines of "Great Britain," by, direct acting screw engines by; trunk engines by. Performance of locomotives. Pillars, hollow, strength of, law of strength varies with thickness of metal. Pipe for receiving screw shaft. Pipes of marine engines. Piston, description of, how to pack with hemp. Pistons, metallic packing for. Pistons for oscillating engines. Pistons, how to fit and finish. Pistons of locomotives. Piston rod, description of, strength proper for. Piston rods of locomotives. Piston rod of oscillating engine. Piston rods of direct acting screw engine. Pitch of the screw. Pitch, increasing or expanding. Pitching motion in locomotives. Planometers, or face plates. Plummer blocks of shafts and trunnions of oscillating engines. Plummer blocks for receiving thrust of screw propeller. Plunger of feed pump. Portable engine, Hoadley's. Porter's patent governor. Ports of the cylinder, area of. Pot-lid valves of air pump. Powers, mechanical, misconception respecting. Power, horses, definition of, nominal and actual power; power of high pressure engines. Power necessary for thrashing and grinding corn, working sugar mills, spinning cotton, sawing timber, grossing cotton, blowing furnaces, driving piles, and dredging earth out of rivers. Pressing cotton, power necessary for. Priming, nature and causes of. Priming, if excessive, may occasion explosion. Propeller, screw, description of. Proportions of screws with, two, four, and six blades. Proving of boilers. Prussiate of potash for case hardening. Pumping engines, mode of erecting, mode of starting. Pumps, loss of effect in, at high speed and with hot water, causes of this loss; remedy for. Pumps used for mines. Pump, air, description, of, action of. Pumps, air, proper proportions of, single and double acting. Pump, centrifugal, better than common pump. Pump, cold water, description of. Pump, feed, description of, action of; proper dimensions of; rule for proportioning; plunger of; valves of; independent. Pump valves for mines, &c. Punching and shearing boiler plates.

Railway wheels, bursting velocity of. Railway trains, resistance of. Rarefaction or exhaustion produced by chimneys. "Rattler" and "Alecto," trials of. Registration, benefits of. Regnault, experiments on heat by. Regulator, a valve for regulating the admission of steam in locomotives, description of; various forms of. Regulator, Clark's, patent steam and fire. Rennie, experiments on friction by. Resistance, experienced by railway trains. Resistance of vessels in water, mainly made up of friction; experiments on. Resistance and speed of vessels influenced by their size. "Retribution," boilers of, by Messrs. Mandslay. Riveting and caulking of land boilers. Rocking motion of locomotives. Rolling circle of paddle wheels. Rotatory engines, definition of. Rotative engines, definition of. Rust joints, how to make.

Safety valve, area of, in low pressure engines, in locomotives. Salinometer, or salt gauge, how to use, how to construct. Salt, accumulation of, prevented in marine boilers by blowing off, if allowed to accumulate in boilers may occasion explosion; amount of, in sea water. Salt water produces surcharged steam. Salting of boilers, what to do if this takes place. Sawing timber, power necessary for. Scale in marine boilers. See also Salt. Scale preventer, Lamb's. Scrap iron, unsuitable for case hardening. Scraping tools for metal surfaces. Screw. Screw engine, geared oscillating, description of, direct acting, description of. Screw engine, direct acting, by Messrs. John Bourne & Co. Screw engines, best forms of. Screw frame in deadwood. Screw propeller, description of. Screw propeller, mode of fixing on shaft, modes of receiving thrust; apparatus for lifting; configuration of; action of; pitch of the screw; screws of increasing or expanding pitch; slip of the screw; positive and negative slip; screw and paddles compared; test of the dynamometer; trials of "Rattler" and "Alecto," and "Niger" and "Basilisk"; indicator and dynamometer power; loss of power in screw vessels in head winds; the screw should be deeply immersed; screws of the Earl of Dundonald, Hodgson, Griffith, Holm, and Beattie; lateral and retrogressive slip; sterns of screw vessels should be sharp; proportions of screws with two, four, and six blades; screw vessels with auxiliary power; screw and paddles combined; economy of fuel in steam vessels; benefits of registration. Screw propeller, Holm's conchoidal. Screw shaft, details of. Screw shaft pipe at stern. Screw shaft brasses of direct acting screw engines. Sea water, amount of salt in. Sea injection cocks. Setting of wagon boilers, of marine boilers. Setting the valves of locomotives. Shaft, paddle, details of. Shaft of screw propeller, details of. Shafts, strength of. Shank's steam gauge. Shocks may not be well resisted by iron that can well resist strains, effect of inertia in resisting shocks. Side levers or beams, description of. Side lever marine engines, description of. Side lever engines, how to erect. Side rods, description of, strength proper for. Silsbee, Mynderse & Co.'s steam fire engine. Single acting engines, definition of. Single acting or pumping engines, mode of erecting; mode of starting. Sinuous motion of locomotives. Slide valve, various forms of; long D and three ported valve, description of; action of the slide valve; lead and lap of the valve; rules for determining the proportions of valves; advantages of lead in swift moving engines. Slide valve, equilibrium. Slide valve with balance piston of direct acting screw engine. Slide valve, how to finish. Slide valves of marine engines, how to set. Slip of paddle wheels. Slip of the screw, positive and negative slip; lateral and retrogressive slip. Smoke, modes of consuming. Smoke burning furnaces, Williams's argand; Prideaux's; Boulton and Watt's dead plate; revolving grate; Juckes's; Maudslay's; Hall's, Coupland's, Godson's, Robinson's, Stevens's, Hazeldine's, &c. "Snake" locomotive. Southern, experiments on friction by; experiments on steam by. Specific heat, definition of. Speed of vessels influenced by their size. Spheroidal condition of water in boilers. Springs of locomotives. Stand pipe for low pressure boilers. Starting handle of locomotives. Staying of boilers. Staying tube plates, mode of. Staying fire boxes of locomotives. Steam, experiments on by Southern, French Academy, Franklin Institute, and M. Regnault. Steam pump, Worthington's; Woodward's. Steam and water, relative bulks of. Steam, expansion of; pressure of; inversely as space occupied; See also Expansion of Steam. Steam engine, applications and appliances of the. Steam engine, general description of Watt's double acting engine; R. Hoe & Co.'s; Corliss's; Woodruff & Beach's. Steam engine, various forms of, for propelling vessels; paddle engines and screw engines; principal varieties of paddle engines; different kinds of paddle wheels; the side lever engine; description of the side lever engine; oscillating paddle engine; description of feathering paddle wheels; direct acting screw engine. Steam dome of locomotives. Steam fire engine, Latta's. Amoskeag. Silsbee, Mynderse & Co.'s. Steam gauge, Bourdon's; Shank's. Steam jacket, benefits of; Steam passages, area of; Steam room in boilers; Steam, surcharged, law of expansion by heat; Steel, strength of; Stephenson, link motion by; Stop valves between boilers; Straight edges; Strains subsisting in machines; Strain proper to be put upon iron in engines; Strains in machines, vary inversely as the velocity of the part to which the strain is applied. aggravated by being intermittent. increase of strain due to deflection. effects of alternate strains in opposite directions. Strength of materials. Strength of hollow pillars, law of; strength varies with thickness of metal. Strength of cast iron to resist shocks does not vary as the strength to resist strains, increase of strength by combination with cast iron. Strength of boilers, experiments on, by Franklin Institute; by Mr. Fairbairn; mode of computing; mode of staying for strength. Strength of engines: cylinder, trunnions; piston rod; main links; connecting rod; studs of the beam; gudgeons; working beam; cast iron shaft; malleable iron shaft; teeth of wheels; side rods; crank; crank pin; cross head; main centre; gibs and cutter. Studs, strength proper for. Stuffing box, description of. Stuffing boxes with metallic packing, with sheet brass packed behind with hemp; sometimes fitted with a lantern, brass. Sugar mills, power necessary to work. Summers' experiments on the friction of rough surfaces. Surcharged steam, law of expansion of, by heat. Surcharged steam produced by salt water, corrosive action of. Surfaces, how to make true. Sweeping the tubes of boilers clean of soot.

Teeth of wheels. Telescope chimneys. Tender of a locomotive, description of, attachment of, to engine. Thrashing corn, power necessary for. Throttle valve, description of. Thrust of the screw propeller, modes of receiving. Thrust plummer block. Tires of locomotive wheels. Traction on railways. Trunk engine by Messrs. Rennie, disadvantages of. Trunk engines by Messrs. Penn. Trunnions of oscillating engines, description of, strength proper for; details of. Trunnion packing. Trunnion plummer blocks. Tube plates, mode of staying. Tube plates of modern locomotives. Tubes of modern locomotive boilers. Tubes of boilers, how to sweep clean of soot. Tubing of boilers. Tubing locomotive boilers.

Valve, atmospheric. Valve casing, description of. Valve casing should have expansion joint. Valve and valve casing of oscillating engine. Valve delivery, description of, action of Valve, equilibrium slide. Valve, foot, description of, action of. Valve gear of Watt's engine, action of. Valve gear of oscillating engine. Valve, gridiron. Valve, slide. See Slide Valve. Valve, slide, how to finish. Valves, ball, Belidor's might be used for foot and delivery valves; butterfly, of air pump; concentric ring, for air pump bucket. Valves, equilibrium. Valves, escape, for cylinders. Valves, expansion. See Expansion Valves. Valves of feed pumps. Valves, india rubber, for air pump. Valves, Kingston's. Valves of locomotives, how to set. Valves, pot-lid, of air pump. Vacuum, meaning of, nature and uses of; how maintained in engines. Vacuum sometimes occurs in boilers, evils of a vacuum in boilers. Vacuum, velocity with which air rushes into a. Vacuum gauge, Bourdon's. Velocity of air entering a vacuum. Velocity of falling bodies. Vent of boilers, definition of. Vessels, resistance of, mainly made up of friction in good forms; experiments on; influence of size. Vis viva, or mechanical power.

Waste steam pipe. Waste water pipe. Water required for condensation, pumps for supplying. Watt's double acting engine, description of. Wedge. Wheels, toothed, for screw engines. Wheels, teeth of. Wheels of locomotives, adhesion of. Wheels, driving, of locomotives. Wheel tires. Wheels and axles of modern locomotives. Wood, experiments on friction by. Wood, evaporative efficacy of. Woodman's steam pump. Woodruff & Beach's steam engine. Working beam of land engine, description of. Worthington's steam pump, duplex pump.

THE END.

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