Rock River Thresheree - Library - Report on Traction Engines





Report on Combined Farm & Traction Engines Think of it as Road & Track for the 1880s...
[The trials of engines conducted by Mr. Hoadley and published below, were made at the Ninth Cincinnati Industrial Exposition, which
was held in 1881 under the direction of a Board of Commissioners representing jointly the Chamber of Commerce, the Board of Trade, and the OHIO MECHANICS' INSTITUTE. A large part of the observations were made by volunteer assistants, from the DEPARTMENT OF SCIENCE AND ARTS, who responded to an invitation of the Chairman, mentioned on page 6 of these PROCEEDINGS. The Publishing Committee is indebted to the courtesy of the Exposition Commissioners for the use of electrotype illustrations, with the
privilege of the simultaneous publication of a part of their Report.]

PART FIRST. - ECONOMY TRIAL.

The three competitors drew the following order of succession:

1. Frick & Co.,
2. Geiser Manufacturing Co.,
3. Huber Manufacturing Co.,
And promptly presented their engines on the three successive days assigned to them, respectively: September 28, 29 and 30; and on the sixth October for the Field Trial.

DYNAMOMETER.

A friction dynamometer, or Prony's brake, of simple construction, was improvised and used with all the engines. A
pulley with very heavy rim, 125.2 in. circumference, 4 in. face, keyed on one end of a shaft, 2.9375 in. diameter, 48 in. long, carried in two inverted drop-hangers fastened to the floor, served as the friction pulley. A belt pulley, 124.925 in. circumference, 8 in. face, placed on this shaft, near the other end, but between the bearings, received a belt from the engine. A beam of ash, 11 ft. long, 4 in. wide, by 8 in. deep in the middle and 4 in. at the ends, fitted to the circumference of the brake pulley for about 18 in. at the middle of its length, served as a brake-beam. A strap of band iron, 3 in. wide by 0.12 in. thick, terminated at the ends by screws 0.87 in. diameter, lined at intervals with maple blocks, formed the binding strap - the screws being carried up through the brake-beam, so as to cause the strap to embrace the lower half of the brake-pulley. A trough, like a grindstone trough, with an inlet and outlet pipe, and a casing of boards on the rising side of the brake pulley, to keep the water from being thrown out, with streams arranged to run on top of the pulley, through holes in the brake-beam, served to disperse the heat by a regulated flow of water. A dash-pot, 5 in. diameter, about 8 in. long, with circulating pipe, ¾ in diameter, from bottom to top, having a cock to
regulate the circulation, and a loosely fitting piston, answered well to moderate the vibrations of the brake-beam, by integrating all transient and opposite impulses, giving, as a net result, a slow upward and downward motion, due to the algebraic sum of such impulses. Near each end, a stop rising from the floor, about 1.25 in. below the bottom of the brake-beam when the latter was level, served to arrest the ascent or descent of its weighted end, if allowed to move so far in either direction from the level position. The entire weight of the balanced brake was counterbalanced by an equal weight, acting by means of a rope over suitable pulleys. The weight which constituted the load to be lifted by friction, was placed on the piston rod of the dash-pot, at a horizontal distance from a vertical line through the axis at the brake pulley of 5.25 feet, giving a circumference of 32 ft., a convenient number, as each 1 pound carried by friction during 1,000 revolutions represented 1 dynamic horse-power. A clock or revolution counter, placed on the brake shaft, and another on the engine shaft, recorded the number of revolutions of each, and, by comparison with the circumference of pulleys, measured with a steel tape, gave the slip, or "creep," of belts here about 1 per cent. This load, alike in all three trials, was made up as follows: Piston and piston rod of dash-pot, 14.25 lbs. Sleeve, nuts and washers, to support weights, 3.25 lbs. 1 iron weight, 25 lbs. 1 iron weight, 25 lbs. 1 iron weight, 10 lbs. 60.00 lbs. Total, unbalanced weight, 77.50 lbs. At each revolution of the brake pulley, while this weight of 77.50 pounds was sustained in a level position of the brake-
beam, by friction at the surface of the pulley, power equal to 77.5x33=2557.5 foot-pounds, was given off by the engine to the dynamometer, and each revolution per minute represented (77.5x33)/33000=0.0775 H.P. dynamic. Reciprocally, 12.9032, or, roughly, 12.9 revolutions per minute represented 1 D.H.P. The whole apparatus being new, neither the concavity in the brake-beam nor the maple blocks in the binding strap fitted
perfectly to the pulley, and the surface of the pulley was somewhat rough, so that a little wearing away of both the wood and the iron was constantly going on, making it necessary to tighten the binding strap from time to time, in order to keep the weights from descending. If this tightening could have been done regularly, and in just the right degree, the brake-beam might have been kept quite steady in the true, level position. This desirable result was sometimes very nearly obtained for hours together. Often, however, a little nervousness or indiscretion on the part of the attendant would give rise to considerable vibration, sometimes as rapid as the dash-pot would permit, and occasionally disastrous in their consequences. When the weights were descending, a part of the load rested on the water in the dash-pot, and its force was expended in driving water upward through the circulating pipe and the leakage at the piston, and the engine, to the extent relieved of its load, was exerting less power. When, on the other hand, the weights were ascending, the resistance of the water in the dash-pot added indefinitely to
the load, up to the whole weight of the atmosphere on the piston area, equal to 19.635x14.7=288.6 pounds. This is 3.7 times the regular load, and of course much more than either of the engines could produce even for an instant,
and explains how an injudicious tightening of the binding strap would cause the almost instantaneous arrest of the engine, which took place once with one engine and repeatedly with another. From the two first engines tested friction cards were taken with a ten-pound spring (the steam being throttled), which agreed very well with the observed difference between the indicated power of the engine and the dynamic power imparted to the brake. In the third case no friction card was taken on account of the lateness of the hour of starting, nearly half-past five in the evening, the absence of an assistant (devolving more arduous duties on the rest), and other circumstances. The observed difference between I.H.P. and D.H.P., as seen at lines 135 and 136 of Table I., was about the same as in the other engines.

GENERAL ARRANGEMENTS OF THE TRIALS FOR ECONOMY OF WATER AND FUEL.

Feed-Water. For keeping a record of the feed-water used, two casks were provided, each set on a pair of 1,000 lb.
Fairbanks' scales, generously lent by the agent of the manufacturers for the purpose. It was intended to draw from the two casks alternately, in the usual maner, recording the weight before and after each draught; but for some reason of supposed convenience all the water was weighed in one cask and poured into the other, from which it was drawn. I have, however, no reason to doubt the accuracy of the log, which was kept by two careful and trained observers, Mr. Walter Laidlaw and Prof. R. B. Warder. A scale, graduated to inches and tenths of an inch, was attached to each glass water gauge, and the height of the water was observed and recorded every quarter of an hour, and very carefully at the beginning and end of the trial, and any observed differences of level allowed for. The temperature of feed-water was noted every fifteen minutes, and the mean temperature, entered in Table I., line 126, is the arithmetical mean of all observed temperatures. The great disparity between the steam expended and the water used in the economy trial of the Frick engine, is to be
explained by a leakage of steam at the valve-rod stuffing-box. At 3 h., 45 min., P.M. the screw stuffer jarred off and the packing was blown out. For a time, while efforts were continued to repack the stuffing-box, the loss of steam was very great; and even after the
stuffer was screwed on over the empty stuffer, the constant leakage was very considerable. The whole duration of this unfortunate leak was 3 h., 36 m., 35 s., equal to 72 per cent. of the whole duration of the trial, and is sufficient, in my judgment, to explain the excessive consumption of water compared with the steam expended. The following considerations will, I think, confirm this opinion. For convenience I have presented the data in tabular form.
The rate of evaporation per square foot of water surface, expressed in cubic inches of steam, per square foot of surface of water per second, will be found at the end of Table I. It will be observed that the area of water surface at the mean water level, line 312, is little different from the area at
normal water level, line 65, 1.1 sq. ft. more in the Huber engine, 4.2 sq. ft. less in the Frick engine, and 1.6 sq. ft. less in the Geiser engine. Huber's rate of ebullition is much the highest, but his water surface is all of nearly equal value, while in both the others, the fire-box and the first foot in length of the flues do far more than the average work of the whole boiler, and their rate of ebullition at and near the fire-box may be as rapid as Huber's mean rate. But the Frick and Geiser boilers are so similar that they may justly be compared in this respect. The Frick has but 20.54 sq. ft. of fire-box heating surface; the Geiser has 26 sq. ft., the former being only 79 per cent. of the latter. The Frick has but 12.6 per cent. of its total heating surface in the fire-box; the Geiser has 22.8 per cent. (il. 16, 19). It is, therefore, probable that the hot gases of the combustion escape from the fire-box and enter the flues at a higher temperature in the Frick engine than in the Geiser, and that the active disengagement of steam from the surface of the water, in a word, the ebullition, may be no more active in the former than in the latter. There can not, at any rate, be much difference, since they differ in the mean rate of ebullition only in the ration of 9:8. Such being the case, it is just to assume that the ratio of water used to steam expended in the Geiser engine may be
properly applied to the Frick. This was the ratio of 35.1 (l. 139, Table I.) to 27.38 (l. 123), an excess of 7.72 lbs. (l.141), equal to 28.19 per cent. (l. 142). Applying this ratio, we must add to 30.52 (l. 123) 28.19 per cent. of itself = 8.6 lbs., making 39.12 lbs., being the quantity of water probably really used by the Frick engine per indicated horse-power per hour. The excess of the actual quantity used, 47.94 lbs., = 8.84 lbs., represents the waste at the valve stem stuffing-box, which had to be evaporated, increasing by about 22 per cent. both the rate of ebullition and the consumption of coal. Aside from this, the run of over five hours was performed with perfect regularity and ease. The plunger of the pump
attached to the cross-head was removed during the trial, and the boiler was supplied by the donkey steam pump - a little increasing the expenditure of steam. The engine ran with quite remarkable steadiness, although only very slightly blocked at the wheels on the floor - the result of excellent counter-balancing, and of the central position of its cylinder. Counter-balances opposite the crank-throw doubtless contributed something to this steadiness. The clearance, 10.18 per cent. of stroke at the end of cylinder nearest to crank, and 12.18 per cent. at the other end, or mean of 11.18 per cent. is excessive, requiring too early exhaust closure if sufficient compression is to be obtained; but even as the clearance is, if the return stroke had been something like equal in economy to the forward stroke, this engine would have surpassed all its rivals in economy of steam. Fuel: Manner of Conducting the Trial. Steam pressure having been raised to about the limit at which the safety-valve
was set - all things being in readiness - fires were drawn, flues were cleaned, fire-box, ash-pit and smoke-box were cleared, and all the partly burned coal, ashes and refuse were taken away. Four pounds of dry shavings and twenty pounds of fine strips of dry white pine were given to each engine for kindling and heating the coal, and for raising the steam pressure, which had fallen off during the process of cleaning, up to the normal, and insuring a fire sufficiently well ignited to maintain regular pressure under the appointed load. At a given signal, fire was set with a match; and at another signal, at a time carefully noted by at least two observers, the starting valve was opened and the trial began. As soon as the engine started, the binding strap of the friction brake was tightened, and the exact time when the weighted arm of the brake-beam rose from its stop was also noted. The middle of this period between engine running light and engine fully loaded was called the "true start," upon the assumption that the application of frictional resistance was uniformly progressive during this period. Coal. This was good, dry Youghiogheny, semi-bituminous, having about 11 per cent. of refuse. No selection was
allowed, but only lumps were used. All coal was brought from the cellar, where it was stored, to the engine by men employed for that purpose by the Commissioners, under the direction of Mr. Harry M. Lane, Superintendent of Machinery Hall. A box three feet square, with sides and a back, but open in the front, was placed on another pair of Fairbanks' 1,000 lb. scales, similar to those used for water, filled with coal, weighed, and the weight was recorded. From this box coal was taken at will by the fireman, the weight remaining being taken after every firing, or at any rate very frequently. In a short test, of only five hours' duration, extreme accuracy is required, and is the more easily attainable in that the close
attention demanded for extreme accuracy is practicable for so short a time. At the expiration of the time, upon a given signal, the engine stopped, and the time of stopping was carefully noted. The fire was drawn and quenched, and fire-box, ash-pit, flues and smoke-box cleaned, and all that was withdrawn was set away in a closet, under lock and key, till the next morning, when the unburned and half-burned coal and ashes were weighed, and the true quantity of coal burned, of refuse left, and of combustible burned, were determined by Mr. Walter Laidlaw and myself. The reading of the revolution counters before and after the run gave the number of revolutions actually made by both engine and dynamometer. For fear of accidents to the counters, the speed of both was taken with an ordinary speed counter during one minute, and every quarter of an hour. A comparison of the relative speed of engine and dynamometer, with the relative circumference of their respective pulleys, also served as a check on the reading of the counters, which, besides, were taken independently by three observers, and compared, while there was still opportunity for revision.

INDICATOR DIAGRAMS.

A Crosby indicator was used, and was found to be well adapted to the speeds which obtained, and very convenient to
manipulate. Diagrams were taken at intervals, not at uniform intervals, since there was no sufficient corps of assistants at hand to
work up a great number of diagrams. This was the less necessary since the load was nearly uniform - quite uniform when the brake-beam was kept steadily level, as already explained. This beam was watched, cards were taken when it was level and at rest, when it was slowly subsiding or slowly rising. A very considerable number of diagrams were measured with the Amster polar planimeter, in the most obliging manner,
by Mr. Frank Lederle, a graduate of the Stevens Institute of Technology. To each line so measured was given a "weight," corresponding to the number of perfect lines on the same card which it fairly represented; the resulting mean effective pressure found for this line was multiplied by its assigned weight, and so mean was obtained fairly representing a considerable number of independent lines. The diagram which best agreed with this mean was selected to represent the mean card, and the normal lines drawn upon it truly represent the mean within the limits of accuracy aimed at. Such complete details of the teaching of these diagrams will be found in Table I., that little need be added. Two wide fields of investigation have, however, been left untouched, namely: the effect of the inertia of the reciprocating parts in modifying the horizontal pressure at the crank, and the influence of the length of the connecting rod on the distribution of tangential pressures, or rotative effect, on the crank. I can only allude to these interesting and important investigations here, as the time necessary for their complete development would far transcend anything contemplated in undertaking these trials. I earnestly commend them to the careful consideration of the parties interested. A new Crosby steam gauge of great delicacy, which had been twice compared with a mercury column just before I left
home, was used on all the engines tested, detached sufficiently to avoid affecting the resilience of the spring by heat. An unfortunate fall at the Exposition having caused some doubt of its accuracy, it was tested twice; first by the Lane & Bodley Company, and again by Wm. Kirkup & Son. The steam gauges attached to the engines, and much affected by heat, all show several pounds higher pressure. See il. 88, 89, Table I. But little remains to be said respecting the separate tests; but some description must be attempted of each engine, and of
its behavior under trial, as well as of the peculiar incidents which in some cases marked its performance.

FRICK & CO.'S ENGINE.

Most of the important dimension of this engine will be found in Table I. Its framing is remarkable for the completeness
with which the boiler is relieved of all strains resulting from the action of the steam engine or running gear. A frame of channel iron, 2x5 in., with suitable girders, wide enough in the clear to allow the fire-box to drop freely into it, is narrowed by an oblique offset on each side, about two feet forward of the fire-box, to a width in the clear of about eighteen inches. A saddle at the forward end, and a band extending around under the fire-box near the hind-axle, support the weight of the boiler without confining it. Plates of iron three-eighths of an inch thick, riveted to the side channel plates of the frame, and extending a little below the frame, to form jaws for the hind ovals, extend high enough to support an arch spanning from side to side, to sustain the weight of the engine bed-plate at its hind end. At the front end the bed-plate rests, by an expansion joint, on a casting riveted to the boiler. The bed-plate, which is in the form of a trough, comes up to a level with the axis of the engine, and its top flange forms the lower slide; the bottom of the near plate of the cross-head being on a level with the axis of cross-head pin. The bottom and one side of the crank-shaft boxes are formed in the solid bed-plate, and are lined with Babbitt metal,
as is the cast-iron cap. The other side of the bearing is formed of a bronze check-piece, held up to its work by two set screws, amd capable of being drawn back far enough when its set screws are withdrawn to be lifted out, and so liberate the shaft. The arrangement of riding springs is ingenious and admirable, but not easy to describe without drawings. The connection
between the gearing and the driving wheels, by means of which the riding springs are allowed free play, and all shocks are taken off the gearing, is very meritorious. Springs in the chain of the steering gear also relieve this gear from severe shocks. An independent pump is useful when the engine is not running. The gears of the equalizing gear are tightly cased, and all the gears are well protected from dirt. There is a convenient brake, for moderating the speed on going down hill, particularly useful when the engine is drawn by
horses. This engine everywhere shows careful study, skilled adaptation of all parts to their office and to each other; and
meritorious originality, conjoined with critical selection of approved forms and methods. A week spent in adjusting the valve, and in equalizing its motion, with the aid of an indicator, might have reduced the
quantity of steam expended by as much as 16 per cent., and so have brought the engine up to the foremost rank in point of economy of heat, as it certainly is in all that relates to design and construction. Trial of the Frick Engine. The trial was attended with few noticeable incidents, and calls for little comment. The untoward jarring loose of the valve-rod stuffer and the blowing out of the packing have already been commented on
at some length. This did not in the least affect the result of the trial, or the relative standing of the engine, as will be seen by consulting il. 121, 122, 123, 156, 157, 158, 159, 170, 171 and 172, Table I., and the diagrams, which are all quite independent of the loss of steam at the stuffer of the valve-rod. Notwithstanding this loss, the harder duty thereby imposed on the boiler, this boiler was, as might have been expected from its much greater heating surface, the most efficient one tested, as will be seen by referring to line 179, of Table I. The heater of this engine was also the most efficient, having an efficiency, derived from heat rejected by the engine, no
less than 7.37 per cent., of the efficiency of the boiler. The speed was noticeably uniform, and the entire run was exempt from all incidents, save the loss of the valve-rod
packing.

THE GEISER MANUFACTURING CO.'S ENGINE.

The excellent engine, designed by Mr. F. F. Landis, and built under his superintendence and in accordance with his
patents, by the Geiser Manufacturing Co., amply repaid long and careful study. It has a semi-frame, not so complete as that of Mr. Frick, but serving to carry the whole fire-box end of the boiler, and
to sustain the driving wheels and the gearing. Cast-iron side pieces replace the three-eighths plates of the Frick engine. The cylinder is on the "off" side of the boiler, and is connected with the crank-shaft boxes by a frame or bed-plate resembling the Corliss bed-plate. The sides are not fitted solid in this bed-plate, in the usual manner, but are adjustable. The advantages of this arrangement can best be ascertained by trial during several years. A noticeable feature is the reversing gear - a modification of the old plan of revolving the eccentric on the shaft from the
proper position for going ahead to the proper position for going backward, and back again. The eccentric is locked to the shaft by a hook. This hook is on a disc keyed upon a shaft, and this shaft is connected with the eccentric by gears, so that they can never change their relative position except as the gears are turned. A hand crank, by means of pulleys, and a short 2 in. belt, communicates motion at will to the hook-disc, its shaft and its gear, and by means of this gear and the one on the eccentric, so that the position of the eccentric is reversed, and the hook (which is double-sided, like the head of a dart) is brought invariably to engage with its notch in the eccentric disc at the right moment. As a mere reverse motion, nothing could be better; but it lacks the important function of a variable expansion gear. A shifting link is a good reverse motion, and much more. The driving wheels have wooden spokes, very cleverly arranged for keeping them always tight. Taking in connection with
the casing of the equalizing gears, the hubs look heavy, and the engine certainly is heavy, as will be seen by reference to lines 289, 290, 291, 292 and 293, Table I., although ten per cent. lighter, without fuel and water, than the Frick engine. The equalizing gear is singularly interesting. It is on the hind axle, and composed entirely of spur-gears, which are
necessarily strong. There are three pairs of pinions, running in sockets upon the ends of their teeth, each pair of sockets overlapping sufficiently to permit the pair of pinions which run in them to engage each other for half their length, to reverse their motion; and each one overlapping its contiguous internally toothed gear sufficiently to allow the other half of each pinion to engage with its gear; one of these gears being, of course, on the adjacent driving wheel, and the other keyed to the axle to which the driving wheel on the other side is also keyed. All this gearing is cased up almost as securely as a hunting-case watch, and runs in most abundant and perfect lubrication; yet all can be taken off, laid out on the floor, examined, and replaced in a few minutes, with the least possible trouble. The flexible and elastic connection between the gearing and the driving wheels, admitting of all useful freedom and motion,
and softening all shocks, such as from striking stones in the road, is apparently all that could be desired. There is a convenient and effective brake, for controlling the engine on descending ground without steam, as when drawn by horses. The diagrams show admirable skill in distributing the inequalities of motion of a single slide-valve, so as to give good
expansion, release and compression, combined with reasonably good admission. The latter is a little tardy on the return stroke. The initial pressure, which is almost always lower at this end (the end farthest from the crank, the "forward" end of a locomotive engine) on account of the higher piston speed at this end, due to the vibration of the connecting rod, accelerating the piston at this end and retarding it at the other, is here depressed to an unusual degree, so that the mean effective pressure of the return stroke is actually 10.2 per cent. lower than that of the forward stroke - a very unusual occurrence. Clearance is very small, only 6.25 per cent. at one end and 7.75 per cent. at the other, a mean of 7 per cent. On the
whole, it would not be easy to point out a way to improve the steam distribution shown by these diagrams in any great degree, with a single slide valve, and no variation in either expansion or compression. The result seen in the consumption of water, and in steam expended per horse-power per hour, 27.38 lbs., which is
remarkably low for a slide-valve, throttling engine, without steam-jacketed cylinder, and would not be thought discreditable to many a large, costly engine, with many refined appliances for saving heat and a good reputation for economy. In common with all the competing engines, the boiler of this Geiser engine is without clothing of any kind. Trial of the Geiser Engine. The start was rather late - 4 h., 8 m., 57 s., P.M. - but excellent friction cards were first
taken, according to which the power consumed in friction was 2.74 H.P. By difference of I.H.P. and D.H.P., 24.22-21.52=2.74, it was substantially the same. The engine ran steadily, almost as steadily as the Frick engine, save a very slight lateral motion, due to the one-sided position of the cylinder, which, by combination with the longitudinal motion, produced a very noticeable gyratory motion. The feed pump attached to cross-head was used, and the independent pump was not started until after the close of the trial. Not a single incident in the least degree abnormal occurred during the trial, until, at 9 h., 1 m., 30 s., just 4 h., 52 h., 33 s. after starting, and just 7 m., 27 s. before the end of 5 full hours, the engine almost instantly stopped. Just 3 minutes later, at 9 h., 4 m., 30 s., the safety valve lifted with a sharp "pop!" showing that the engine did not stop for want of steam. Examination soon revealed that its stoppage was not due to any breakage or disarrangement of any of its parts, and
subsequent investigation revealed the cause. As the run was thought by all to be about terminated, the man who was attending to the brake left his post to take part in
the preparations for drawing the fire after the close of the trial. Before leaving, he was seen by Mr. Harry M. Lane to give a good pull to the wrench in the direction of tightening the binding strap - as this man himself says, to prevent the loaded end of the brake from subsiding, by the slight wear of the parts already explained. Tightening the binding strap a little too much, the weighted end rose until the other end struck its stop, when the resistance thus suddenly increased became greater than the engine with full steam pressure and full throttle could overcome, and it of necessity stopped almost instantly. The time was so nearly up, and the engine was so obviously not to be blamed for an accident to the dynamometer not resulting in the least damage to the engine, that the trial was pronounced closed, and the fire was drawn, quenched, and put away till morning. The engine suffered a little loss by the burning away of some coal during the few moments of indecision before directions
to draw the fire were given; but this loss must have been small, as the time was short, not exceeding two minutes. The water was a little low at stopping, but the deficit, 75.7 lbs., was pumped in by the donkey pump, first started for that
purpose; the steam pressure was taken after the water was brought to the same level as starting, and due allowance was made for difference of pressure. I have been thus explicit because this awkward stop has given rise to some comment, and may give rise to more; and
because I am fully satisfied that the engine could not be blamed for it, gained nothing by it, and should suffer nothing in consequence of this curtailment of the time by less than 2.5 per cent. The coal charged to the engine, and reckoned as consumed, was nearly sufficient to complete the full five hours; yet credit was given only for the time actually run.

THE HUBER MANUFACTURING CO.'S ENGINE.

This engine, designed by Mr. Huber, and built under his superintendence, is noticeable for many peculiarities and much
originality and boldness. It would be indeed remarkable if all the innovations upon approved practice here combined were real improvements, but one or more of them seem to me to be worthy of study, of trial, perhaps of general adoption. In general appearance the whole machine is "chubby," clumsy, and unprepossessing, and it certainly should have been better constructed; but, with all its shortcomings, both of detail and performance, it is rare that so much efficiency has been obtained from so small an amount of material, both in bulk and weight, as will be found in this engine. It is very short, only about six feet over all, save the narrow foot-board, so that its wheels, all small, are brought close together. Very short in the water space, only 4 ft., 6 in., and 3 ft. in diameter, with a dome 16 in. diameter nearly in the middle of its length; grades, ascending or descending, are of little consequence to it as affecting its water level. The engine is vertical on the "off" or right hand side, partly covered by the driving wheel. Its factor of traction, obtained by multiplying together the number of cubic feet in the volume swept through by the piston per revolution, and the number of revolutions of the engine shaft per mile run, without slip; and dividing this product by the weight of the engine in running order (see line 280, Table I.) is very large, .258 - 32 per cent. larger than in the Frick engine (.196) and 47 per cent. larger than in the Geiser engine (.176). This, in connection with the lighter load it drew over the hard places, and an arrangement to be explained for connecting the drivers, will explain its apparently remarkable performance at Tower Hill on the field trial. Its supplementary feed-water heater around the smoke-box, together with its capacious water tank carried ahead of its enlarged smoke-box, gives it a top-heavy appearance, and this considerable weight so far forward on an engine with so short a wheel-base, must diminish the adhesion of the drivers on level ground, while rather assisting it on steep ascents. The simple and effectual method of coupling together the two drivers, rendering the equalizing gear for the time
inoperative, and compelling each driving wheel to help the other, proved its utility at Tower Hill, and will again be referred to. Carrying the steam-pipe down through a sleeve in the steam and water space, through the fire-box in its hottest part, and
through another sleeve in the lower water space, may help to give dry steam, and did, I think, prove itself useful in that way, but might be considered hazardous with a hot fire and steam current all shut off, even at the lower end, since the steam confined in this pipe might become intensely superheated, communicating with the steam space of the boiler, as it does at the top of the dome, through the governor throttle. The most meritorious novelty is the link-reversing motion. A short hand-wheel shaft carries on its forward end a beveled pinion, arranged to slide on a "feather" or spline in the shaft. This beveled pinion engages with a beveled segment on the side of a shifting link, and by turning the hand wheel the link is raised or lowered - reversing the engine or varying the cut-off, at pleasure. The axis of this pinion being exactly on a level with the center of the valve stem, the link block has no sliding motion, no "slip," and consequently little wear. On the other hand, the pinion slides backward and forward at every stroke of the engine. How far the wear these parts
must suffer may counter-balance the saving of wear at the link block can only be ascertained by experience. Trial of the Huber Engine. The start was late - 5 h., 26 m., 50 s., P.M. - about dark, and one of our best observers,
Prof. Warder, was otherwise engaged. No friction cards were taken, as that would have delayed the start till nearly seven o'clock. No exact measurement of the circumference of the 32 in. pulley (so-called) was taken, and taking this as the diameter at the edge, the computed circumference, 108.8 in., gives a slip of belt equal to 2.6 per cent. In the previous cases it was 0.9 per cent. to 1.0 per cent., and the circumference of Mr. Huber's pulley may have varied slightly from the estimate. Too much was attempted. The same load on the brake, 77.5 lbs., which, with 248.54 revolutions of the brake shaft per minute, gave the Frick engine 19.26 D.H.P., and which, with 277.71 revolutions per minute, gave the Geiser engine 21.52 D.H.P., gave the Huber engine only 16.63 D.H.P., with 214.64 revolutions of the brake shaft, and 273.52 revolutions of the engine shaft per minute. This, it is true, was about the same loss in proportion to either of the others; but in view of its very restricted heating surface it was excessive. To carry this heavy load, 16.63 D.H.P., 18.84 I.H.P., with an engine having only 7 in. cylinder diameter and 8 in. stroke, with no more than 364.71 ft. per minute piston speed, required of course, a high mean effective pressure; and to generate steam to maintain this pressure with a boiler having only 71.55 sq. ft. of heating surface, counting the whole surface of the supplementary heater around the smoke-box, of course required a small blast-pipe. Mr. Huber also thought it advisable to set the throttle valve of his Waters' governor that it could not much reduce the
pressure at any speed attained, and therefore held in reserve little power, of any, to meet a sudden augmentation of resistance. In consequence of this attempt to run without reserved pressure, "from hand to mouth," in connection with the various resistance of which I have spoken at length in the account of the trial of the Geiser engine, this Huber engine stopped no less than six times, including the final stop at 10 h., 30 m., 40 s., which was a few minutes earlier than I intended to close the trial, but too near the end to be worth while to start again. The following abstract of the time-log will give an idea of the unexpectedness of these stops:
Steam pressure was very well maintained, and was never low enough during the whole trial to account for stopping;
indeed the engine ran along smoothly at the lowest recorded pressures, and at some of the stoppages the pressure was about at its highest. The explanation I have already given in the case of the Geiser engine is, doubtless, a true explanation here. Water level varied a good deal. It was occasionally quite at the top of the tube of the glass water gauge, and oftener
almost at the bottom. The mean is very low (il. 124), and much of the time it must have left the upper row of 3-in. return flues partly uncovered. Hazardous as this may have been, it doubtless helped to give the extremely dry steam that was generally supplied to the cylinders, although there were instances not a few of priming, when the water was high, and when an overflow pipe from the heater was carrying a good deal of oil into the feed-water barrel. This last practice was discontinued early in the trial, and this overflow allowed to run to waste, which caused an unknown amount of loss. It seems difficult to understand the small excess of water used over steam expended (il. 141, 142) in view of this lost
water, of the not infrequent instances of excessive priming, and of the hard work required of the boiler, without the assumption that the partly uncovered flues and the passage of the steam pipe through the fire may have given, during a large part of the time, unusually dry steam. The diagrams do not call for much comment, as their character is stamped on their face. With a more judicious load, say
10 to 12 horse power, dynamic, with the link properly set in view of this lighter load, and with a blast-pipe nozzle 1[in. or 1¼ in. diameter, which would have made sufficient draught, and would have caused much less back pressure, this engine might have ranged close up to the others in performance, and would certainly have performed its task without fault. A word about draught, applicable to all the engines tested. A 12 in. pipe, with an elbow nearly a full right angle, but
rounded to about one foot radius on the inner side, entered a chimney 12 in. square at about 19 ft. from the floor. It was intended to enter the chimney obliquely, but was carried in about at right angles, making a square turn at the chimney, which was about 45 ft. high from the floor on which the engines stood, say about 43 ft. high above the grates. This chimney certainly did not aid the draught, and sometimes obviously obstructed it. It will be admitted, I think, that no possible manipulation of the data obtained at these economy tests could modify the
relative rank I assign to the competing engines, with respect to economy or the result of the tests: 1. The Geiser Engine. 2. The Frick Engine. 3. The Huber Engine.
TABLE I.
[click on images for full-sized versions]

INDICATOR DIAGRAMS.
No. 1. Mean diagram taken from the Huber engine during the economy test, September 30, 1881, at 9 h., 8 m., P.M. Cut-off differs too much at the two ends, and is too late at both ends. The excessive back pressure is due to the small blast-pipe nozzle - 0.75 in. See lines 121, 122, 123, of the preceeding table.
No. 2. Mean diagram from the Frick engine, taken during the trial, September 28, 1881, at 3 h., 30 m., P.M. The card from the end of the cylinder nearest the crank, descending to the left hand, is very good for a throttling engine; and with a little less clearance, and a little more compression, would be excellent. As it is, it gives the best results of any single-end card taken during the trials. Had the other end been as good, relatively, this engine would have stood at the head in the economy trials. The effect of late releasing in causing excessive back-pressure is seen on this card. See lines 121, 122, 123, of foregoing table.
No. 3. Mean diagram from the Geiser engine, taken during the trial, September 29, 1881, at 8 h., 7 m., P.M. Both these cards are remarkably good. Clearance 7.25 per cent. at crank end, and 6.25 per cent. at the out end - a mean of 7 per cent. Exhaust closure is about alike at the ends, but compression is a little less complete in the forward stroke, on account of the greater length of clearance at that end. This card actually contained five full lines, taken at intervals of three seconds - pretty evenly shading the spaces between the lines drawn in ink and engraved. It was selected from cards representing 172 full lines from each end of cylinder, because it almost exactly corresponded to the mean of all. The full, normal lines truly represent such mean. Admission is a little late on return stroke, probably on account of the nice equalization of the other events. Both admission and cut-off should be a little earlier at this end, and earlier release, and even earlier exhaust-closure would do no harm. A study of these cards, and of lines 121, 122 and 123 of the table, will reveal the cause of every good and bad result of the various valve-adjustments at each end of these three cylinders - practically, six engines, so far as the use of steam is concerned.

PART FIRST. - FIELD TRIAL, OCTOBER 6, 1881.
(A table is appended to this paper, showing the grades at the different part of the route, and compiled from a profile map that appears in the Exposition Report. - Eds.) A detachment of mounted police, courteously furnished by the City Government, or Mayor, served to keep intrusive
curiosity at just sufficient distance, and guarded against danger of frightening horses, and proved very useful. The day was all that could be desired. Recent rains had laid the dust, and had so softened the ground in some parts of
the route as to task the tractive qualities of the engines to the utmost. The air was cool, and there was a gentle breeze. The Load. Each engine was required to draw, besides a full supply of water and fuel, at least 3,500 pounds, equal to
the weight of a 42-in. separator, the arrangement of this load being left to the discretion of each exhibitor, as well as the actual load which each might undertake to draw. (The load brought back to the Exposition building was of little consequence, as it was drawn, mostly, down hill. It was the load drawn up Vine Street Hill, Tower Hill, and a few other places, that really tested the engines. - J.C.H.) Mr. Landis took from the Exposition building, as a load for the Geiser Manufacturing Company's engine:
Tender wagon, with water and coal, at start
4,200 lbs.

Passenger wagon, with 16 men, including firemen and observers, who in fact rode on the engine
4,100 lbs.

One man, not weighed with wagon
140 lbs.

Total

8,440 lbs.

The load which he brought back was:
Wagon, with coal and water
2,137 lbs.

Wagon, 15 men
3,940 lbs.

The one man before weighed
140 lbs.

Total

6,217 lbs.

But a part of this load was detached, as we shall see, on ascending Tower Hill. This engine also took two barrels of
water on the way, weighing, net, 734 pounds. Mr. Frick procured a city watering wagon, weighing, with its contents, at starting, 7,830 pounds, and at the end of the
run, 5,035 lbs. This load was never detached, save when the engine slipped into a deep mudhole, at 3 h., 31 m. P.M., and the wagon was then drawn out by a rope by the engine, and connected again in a few minutes. Mr. Huber started from the Exposition building with a passenger wagon, containing a number of men in addition to his
tender wagon, with water and coal; but, as he was obliged to detach this passenger wagon at 12 h., 30 m., before ascending Vine Street Hill, no account is here taken of it. His tender wagon, with water and coal, weighed, at starting, 3,450 lbs., and at the end of run, 1,251 lbs. See lines 297, 298, 299, Table I. The Start. The time set for starting was 10 A.M., but numerous causes delayed it until noon. Steam having been raised,
the fires were all drawn, and 4 lbs. of shavings and 20 lbs. of kindling wood were furnished to each engine. By a misapprehension of the order, upon the signal for starting fires, the Geiser engine started on the race, but was halted to wait for the arrival of the rest at Green Street, where the true start was made at 12 h., 10 m., 0 s., P.M. Two observers accompanied each engine, one instructed to record all that concerned the steam engine, the other to pay particular attention to the scale of the road and the performance of the running-gear. Mr. Walter Laidlaw accompanied me in a carriage, and we were able, for a considerable part of the way, to take pretty full notes of the working of at least two of the engines, and sometimes of all three. At Tower Hill, where the most severe test of their powers was applied, each engine made the ascent and descent separately, so that all were fully noted. Water Used. The quantity of water used was satisfactorily ascertained, save the doubt that attaches to the suspiciously
round numbers given by the city scales, on which the weighing was done. There is no other reason to doubt its accuracy. Not so with the coal. Although very accurately weighed to start with, an unknown quantity was lost off from two of the engines, and in one case the fire, drawn from the fire-box at the end of the run, was not weighed. No way remained, therefore, but to take the rate of evaporation that had been found at the economy trial and apply it to
the quantity of water used in the field trial. In the one case, in which the quantity of coal used was determined, the agreement with the evaporation at the economy trial was very close, and it is to be presumed that an almost equally close agreement would have been obtained if the quantity of coal burned had been known. The coal was the same as before, best Youghiogheny.

INDICATOR DIAGRAMS.

The indicators used were a pair of Thompson indicators, made by the American Steam Gauge Company, Boston. One
of them had been used at a high speed during the Exposition, and its barrel-spring had been tightened for that purpose. The fact that the other one had not been tightened was overlooked, so that this indicator, which by chance was placed on the Frick engine, could only be used at low speeds. The diagrams obtained show exactly the same characteristics as those from the same engine at the economy trial, already commented on. The other indicator was placed on the Geiser, and gave some interesting diagrams, which will be briefly noticed later. No diagrams could be taken from the Huber engine while running on the road, on account of the location of its cylinder partly behind the driving wheel.

Diagram No. 4 (Frick) Diagram No. 5 (Geiser) Diagram No. 6 (Geiser) Diagram No. 7 (Geiser) Diagram No. 8 (Geiser) Diagram No. 9 (Geiser)

FIELD TRIAL OF
COMBINED TRACTION AND FARM ENGINES.
[In 5 parts]

GENERAL REMARKS.

The incidents of the trial are all so fully detailed in the preceding log, although somewhat condensed, that it seems
unnecessary to go over in detail all the adventures and misadventures of each engine, I will, therefore, confine myself to such general comments as may occur to me, in almost any order in which they may present themselves, often by comparison of one engine with another. The conspicuous defects of workmanship in the Huber engine proved their serious importance by the frequent "accidents"
which befell this engine. Its peculiar form of corrugations on the face of its driving wheels demonstrated its unfitness for all conditions of road, by the extreme difficulty with which the engine was made to cross street railways; but it may answer well on some farming land. Its great climbing qualities, due in part to its large factor of traction (l. 280, Table I.), and in part to the contrivance for coupling the two driving wheels together, were demonstrated at Tower Hill, where it passed in 10 m., 15s., over the route which detained the Geiser engine 42 m., 38 s., and the Frick engine no less than 1 h., 22 m., 5 s. In performing this feat the Huber drew up Tower Hill 2,350 lbs., equal to 28.7 per cent. of its own weight in running order (l. 291), and 33.5 per cent. of its own net weight (l. 293); while the Geiser had, in going up this same hill, 3,181 lbs., only 23.7 per cent. of its own weight, with water and fuel (l. 291), and 27.3 per cent. of its own net weight (l. 293). The Frick engine had much more than either of the others, namely: 6,168 lbs., equal to 47.1 per cent. of its weight in running order, and no less than 57.9 per cent. of its own net weight. This performance of Mr. Prick's engine displayed great staying qualities on the part of man and engine alike; but the method he pursued would enable any engine to get out of any hole in time. This method consisted of macademizing the rut under the sunken wheel with stones, alternately before and behind the wheel, and running forward and back upon the causeway so formed, until the wheel was lifted high enough to run off upon the ground in front of it, not too far from a level. To persist in doing this for more than an hour, with three tons load on behind, was plucky, and in the end successful; but it could have been done in less time if the load had been detached and again picked up after "treading the road." I was watching the Geiser engine when the near driver struck the small tree mentioned in the log—stood within a yard of
the tree—and am confident that but for this tree the engine would have gone along without stopping. The ground was no worse than that already passed over for several yards; but the tree bent to the curve of the tire, its bark was instantly scraped off, and the slimy surface of the naked wood offered no hold for the corrugations of the tire, while preventing them from taking hold of the ground in front of the wheel. The remarkable ease with which the equalizing gears ran, noticeable at the Exposition, permitted this wheel to turn freely while the other remained motionless, and the corrugations dug a pit ever deeper for the idly revolving wheel. It was the opinion of several competent witnesses, as well as my own opinion, that the ordinary device of locking the
equalizing gears would have enabled both the Geiser engine and the Frick to go over the entire route, actually run, with little detention, if any. The performance of the Geiser engine, in running up Vine Street Hill, was every way admirable. The Frick did almost as
well, and would, I think, have done quite as well had its valve been properly set. The same inequality of the two strokes which showed itself in the friction card, with 10 lb. spring, and in all the diagrams at the economy trial, is seen in diagram No. 4 (p. 85), one of three all much alike, taken at 1 h., 46 m., 0 s., P.M., while the engine was struggling in the hole on Tower Hill. The five cards from the Geiser engine (Nos. 5-9) show the same persistency of qualities and defects. It will be observed that in these cards the strokes are transposed from their position in the one given above as a mean of
all the diagrams taken at the economy test; while the one below, from the Frick engine, is not so transposed. This is on account of the way in which the indicators happened to be adjusted. The five diagrams from the Geiser engine, under various conditions, are very instructive. Supposing the speed to be uniformly as during the economy trial, i. e., controlled by the governor, the power required
on a level road was 4.36 I.H.P. (4 h., 35 m., 0 s., P.M.). Again, also on a level road, but presumably a worse one, at 3 h., 47 m., 0 s., 12.93 I.H.P. Going up the steep Vine Street Hill, road very smoth, 16.11 I.H.P. At the steep grade, on soft ground, at the reversed curve, Prospect and Glenway Avenues, the mean effective pressure, with normal speed, would represent 27.22 I.H.P.; while, just before stopping, 1 h., 11 m., 10 s., a pressure was exerted in the cylinder, which, at normal speed, would be capable of exerting 32.54 I.H.P. The mean of all observed steam gauge pressures, pretty regularly taken during the run, are:
Huber 98.12 pounds per square inch Frick 116.9 pounds per square inch Geiser 115.6 pounds per square inch These pressures are probably all subject to four or five pounds reduction, on account of the softening of the springs at
the steam gauges by heat, as already explained with regard to 1l. 88, 89, Table I. While it is certain that in this competition the engine of the Geiser Manufacturing Company is the victor at all points, it is
by no means certain that it is to the same degree superior to its nearest rival, the Frick engine. I have presented elsewhere my views upon the chief points of difference between them. Both were in perfect order
during and after the trial; both are good engines, and I predict for both a great future, when they are made to do their work with an expenditure not exceeding thirty pounds of water per horse-power (indicated), and per hour. I desire, in conclusion, to tender my sincere thanks to the assistants who gave me most valuable aid, with untiring devotion, especially Mr. Walter Laidlaw, Prof. R. B. Warder, and Mr. E. H. St. John. Of Mr. Frank Lederle's assistance, in making planimeter measurements of diagrams, I have spoken elsewhere. I regretted the too early privation of Mr. Newton M. Anderson's assistance. Mr. Harry M. Lane, Mr. F. Bain, Mr. E. A. Edwards, and Mr. Alfred R. Payne, also gave valuable help, particularly at the field trial.
Table of Grades in the Route of the Field Trial.

BIBLIOGRAPHY:

Hoadley, J. C. "Report on Combined Farm & Traction Engines." Scientific Proceedings of the Ohio Mechanics Institute, Vol. I. Ed. Robert

B. Warder. Cincinnati: Ohio Mechanics Institute, Department of Arts & Sciences, 1882; pp. 54-97

Piston and piston rod of dash-pot,		14.25 lbs.
Sleeve, nuts and washers, to support weights,		3.25 lbs.
1 iron weight,	25 lbs.
1 iron weight,	25 lbs.
1 iron weight,	10 lbs.	60.00 lbs.
Total, unbalanced weight,		77.50 lbs.