The conductor stood at the end of the train, watch in hand, and at the moment when the hands indicated the appointed hour he leisurely climbed aboard and pulled the whistle cord. A sharp, penetrating hiss of escaping air answered the pull, and the train moved out of the great train-shed in its race against time. It was all so easy and comfortable that the passengers never thought of the work and study that had been spent to produce the result. The train gathered speed and rushed on at an appalling rate, but the passengers did not realise how fast they were going unless they looked out of the windows and saw the houses and trees, telegraph poles, and signal towers flash by.
It is the purpose of this chapter to tell how high speed is attained without loss of comfort to the passengers—in other words, to tell how a fast train is run.
When the conductor pulled the cord at the rear end of the long train a whistling signal was thus given in the engine-cab, and the engineer, after glancing down the tracks to see that the signals indicated a clear track, pulled out the long handle of the throttle, and the great machine obeyed his will as a docile horse answers a touch on the rein. He opened the throttle-valve just a little, so that but little steam was admitted to the cylinders, and the pistons being pushed out slowly, the driving-wheels revolved slowly and the train started gradually. When the end of the piston stroke was reached the used steam was expelled into the smokestack, creating a draught which in turn strengthened the heat of the fire. With each revolution of the driving-wheels, each cylinder—there is one on each side of every locomotive—blew its steamy breath into the stack twice. This kept the fire glowing and made the chou-chou sound that everybody knows and every baby imitates.
As the train gathered speed the engineer pulled the throttle open wider and wider, the puffs in the short, stubby stack grew more and more frequent, and the rattle and roar of the iron horse increased.
Down in the pit of the engine-cab the fireman, a great shovel in his hands, stood ready to feed the ravenous fires. Every minute or two he pulled the chain and yanked the furnace door open to throw in the coal, shutting the door again after each shovelful, to keep the fire hot.
The fireman on a fast locomotive is kept extremely busy, for he must keep the steam-pressure up to the required standard—150 or 200 pounds—no matter how fast the sucking cylinders may draw it out. He kept his eyes on the steam-gage most of the time, and the minute the quivering finger began to drop, showing reduced pressure, he opened the door to the glowing furnace and fed the fire. The steam-cylinders act on the boiler a good deal as a lung-tester acts on a human being; the cylinders draw out the steam from the boiler, requiring a roaring fire to make the vapour rapidly enough and keep up the pressure.
Though the engineer seemed to be taking it easily enough with his hand resting lightly on the reversing-lever, his body at rest, the fireman was kept on the jump. If he was not shovelling coal he was looking ahead for signals (for many roads require him to verify the engineer), or adjusting the valves that admitted steam to the train-pipes and heated the cars, or else, noticing that the water in the boiler was getting low—and this is one of his greatest responsibilities, which, however, the engineer sometimes shares—he turned on the steam in the injector, which forced the water against the pressure into the boiler. All these things he has to do repeatedly even on a short run.
The engineer—or "runner," as he is called by his fellows—has much to do also, and has infinitely greater responsibility. On him depends the safety and the comfort of the passengers to a large degree; he must nurse his engine to produce the greatest speed at the least cost of coal, and he must round the curves, climb the grades, and make the slow-downs and stops so gradually that the passengers will not be disturbed.
To the outsider who rides in a locomotive-cab for the first time it seems as if the engineer settles down to his real work with a sigh of relief when the limits of the city have been passed; for in the towns there are many signals to be watched, many crossings to be looked out for, and a multitude of moving trains, snorting engines, and tooting whistles to distract one's attention. The "runner," however, seemed not to mind it at all. He pulled on his cap a little more firmly, and, after glancing at his watch, reached out for the throttle handle. A very little pull satisfied him, and though the increase in speed was hardly perceptible, the more rapid exhaust told the story of faster movement. As the train sped on, the engineer moved the reversing-lever notch by notch nearer the centre of the guide. This adjusted the "link-motion" mechanism, which is operated by the driving-axle, and cut off the steam entering the cylinders in such a way that it expanded more fully and economically, thus saving fuel without loss of power.
When a station was reached, when a "caution" signal was displayed, or whenever any one of the hundred or more things occurred that might require a stop or a slow-down, the engineer closed down the throttle and very gradually opened the air-brake valve that admitted compressed air to the brake-cylinders, not only on the locomotive but on all the cars. The speed of the train slackened steadily but without jar, until the power of the compressed air clamped the brake-shoes on the wheels so tightly that they were practically locked and the train was stopped. By means of the air-brake the engineer had almost entire control of the train. The pump that compresses the air is on the engine, and keeps the pressure in the car and locomotive reservoirs automatically up to the required standard.
Each stage of every trip of a train not a freight is carefully charted, and the engineer is provided with a time-table that shows where his train should be at a given time. It is a matter of pride with the engineers of fast trains to keep close to their schedules, and their good records depend largely on this running-time, but delays of various kinds creep in, and in spite of their best efforts engineers are not always able to make all their schedules. To arrive at their destinations on time, therefore, certain sections must be covered in better than schedule time, and then great skill is required to get the speed without a sacrifice of comfort for the passenger.
To most travellers time is more valuable than money, and so everything about a train is planned to facilitate rapid travelling. Almost every part of a locomotive is controlled from the cab, which prevents unnecessary stopping to correct defects; from his seat the engineer can let the condensed water out of the cylinders; he can start a jet of steam in the stack and create a draft through the fire-box; by the pressure of a lever he is able to pour sand on a slippery track, or by the manipulation of another lever a snow-scraper is let down from the cowcatcher. The practised ear of a locomotive engineer often enables him to discover defects in the working of his powerful machine, and he is generally able, with the aid of various devices always on hand, to prevent an increase of trouble without leaving the cab.
As explained above, a fast run means the use of a great deal of steam and therefore water; indeed, the higher the speed the greater consumption of water. Often the schedules do not allow time enough to stop for water, and the consumption is so great that it is impossible to carry enough to keep the engine going to the end of the run. There are provided, therefore, at various places along the line, tanks eighteen inches to two feet wide, six inches deep, and a quarter of a mile long. These are filled with water and serve as long, narrow reservoirs, from which the locomotive-tenders are filled while going at almost full speed. Curved pipes are let down into the track-tank as the train speeds on, and scoop up the water so fast that the great reservoirs are very quickly filled. This operation, too, is controlled from the engine-cab, and it is one of the fireman's duties to let down the pipe when the water-signal alongside the track appears. The locomotive, when taking water from a track-tank, looks as if it was going through a river: the water is dashed into spray and flies out on either side like the waves before a fast boat. Trainmen tell the story of a tramp who stole a ride on the front or "dead" end platform of the baggage car of a fast train. This car was coupled to the rear end of the engine-tender; it was quite a long run, without stops, and the engine took water from a track-tank on the way. When the train stopped, the tramp was discovered prone on the platform of the baggage car, half-drowned from the water thrown back when the engine took its drink on the run.
"Here, get off!" growled the brakeman. "What are you doing there?"
"All right, boss," sputtered the tramp. "Say," he asked after a moment, "what was that river we went through a while ago?"
Though the engineer's work is not hard, the strain is great, and fast runs are divided up into sections so that no one engine or its runner has to work more than three or four hours at a time.
It is realised that in order to keep the trainmen—and especially the engineers—alert and keenly alive to their work and responsibilities, it is necessary to make the periods of labour short; the same thing is found to apply to the machines also—they need rest to keep them perfectly fit.
Before the engineer can run his train, the way must be cleared for him, and when the train starts out it becomes part of a vast system. Each part of this intricate system is affected by every other part, so each train must run according to schedule or disarrange the entire plan.
Each train has its right-of-way over certain other trains, and the fastest train has the right-of-way over all others. If, for any reason, the fastest train is late, all others that might be in the way must wait till the flyer has passed. When anything of this sort occurs the whole plan has to be changed, and all trains have to be run on a new schedule that must be made up on the moment.
The ideal train schedules, or those by which the systems are regularly governed, are charted out beforehand on a ruled sheet, as a ship's course is charted on a voyage, in the main office of the railroad. Each engineer and conductor is provided with a printed copy in the form of a table giving the time of departure and arrival at the different points. When the trains run on time it is all very simple, and the work of the despatcher, the man who keeps track of the trains, is easy. When, however, the system is disarranged by the failure of a train to keep to its schedule, the despatcher's work becomes most difficult. From long training the despatchers become perfectly familiar with every detail of the sections of road under their control, the position of every switch, each station, all curves, bridges, grades, and crossings. When a train is delayed and the system spoiled, it is the despatcher's duty to make up another one on the spot, and arrange by telegrams, which are repeated for fear of mistakes, for the holding of this train and the movement of others until the tangle is straightened out. This problem is particularly difficult when a road has but one track and trains moving in both directions have to run on the same pair of rails. It is on roads of this sort that most of the accidents occur. Almost if not quite all depends on the clear-headedness and quick-witted grasp of the despatchers and strict obedience to orders by the trainmen. To remove as much chance of error as possible, safety signalling methods have been devised to warn the engineer of danger ahead. Many modern railroads are divided into short sections or "blocks," each of which is presided over by a signal-tower. At the beginning of each block stand poles with projecting arms that are connected with the signal-tower by wires running over pulleys. There are generally two to each track in each block, and when both are slanting downward the engineer of the approaching locomotive knows that the block he is about to enter is clear and also that the rails of the section before that is clear as well. The lower arm, or "semaphore," stands for the second block, and if it is horizontal the engineer knows that he must proceed cautiously because the second section already has a train in it; if the upper arm is straight the "runner" knows that a train or obstruction of some sort makes it unsafe to enter the first block, and if he obeys the strict rules he must stay where he is until the arm is lowered At night, red, white, and green lights serve instead of the arms: white, safety; green, caution; and red, danger. Accidents have sometimes occurred because the engineers were colour-blind and red and green looked alike to them. Most roads nowadays test all their engineers for this defect in vision.
In spite of all precautions, it sometimes happens that the block-signals are not set properly, and to avoid danger of rear-end collisions, conductors and brakemen are instructed (when, for any reason, their train stops where it is not so scheduled) to go back with lanterns at night, or flags by day, and be ready to warn any following train. If for any reason a train is delayed and has to move ahead slowly, torpedoes are placed on the track which are exploded by the engine that comes after and warn its engineer to proceed cautiously.
All these things the engineer must bear in mind, and beside his jockey-like handling of his iron horse, he must watch for signals that flash by in an instant when he is going at full speed, and at the same time keep a sharp lookout ahead for obstructions on the track and for damaged roadbed.
The conductor has nothing to do with the mechanical running of the train, though he receives the orders and is, in a general way, responsible. The passengers are his special care, and it is his business to see that their getting on and off is in accordance with their tickets. He is responsible for their comfort also, and must be an animated information bureau, loaded with facts about every conceivable thing connected with travel. The brakemen are his assistants, and stay with him to the end of the division; the engineer and fireman, with their engine, are cut off at the end of their division also.
The fastest train of a road is the pride of all its employees; all the trainmen aspire to a place on the flyer. It never starts out on any run without the good wishes of the entire force, and it seldom puffs out of the train-shed and over the maze of rails in the yard without receiving the homage of those who happen to be within sight. It is impossible to tell of all the things that enter into the running of a fast train, but as it flashes across States, intersects cities, thunders past humble stations, and whistles imperiously at crossings, it attracts the attention of all. It is the spectacular thing that makes fame for the road, appears in large type in the newspapers, and makes havoc with the time-tables, while the steady-going passenger trains and labouring freights do the work and make the money.
Every boy and almost every man has longed to ride on a locomotive, and has dreamed of holding the throttle-lever and of feeling the great machine move under him in answer to his will. Many of us have protested vigorously that we wanted to become grimy, hard-working firemen for the sake of having to do with the "iron horse."
It is this joy of control that comes to the driver of an automobile which is one of the motor-car's chief attractions: it is the longing of the boy to run a locomotive reproduced in the grown-up.
The ponderous, snorting, thundering locomotive, towering high above its steel road, seems far removed from the swift, crouching, almost noiseless motor-car, and yet the relationship is very close. In fact, the automobile, which is but a locomotive that runs at will anywhere, is the father of the greater machine.
About the beginning of 1800, self-propelled vehicles steamed along the roads of Old England, carrying passengers safely, if not swiftly, and, strange to say, continued to run more or less successfully until prohibited by law from using the highways, because of their interference with the horse traffic. Therefore the locomotive and the railroads throve at the expense of the automobile, and the permanent iron-bound right of way of the railroads left the highways to the horse.
The old-time automobiles were cumbrous affairs, with clumsy boilers, and steam-engines that required one man's entire attention to keep them going. The concentrated fuels were not known in those days, and heat-economising appliances were not invented.
It was the invention by Gottlieb Daimler of the high-speed gasoline engine, in 1885, that really gave an impetus to the building of efficient automobiles of all powers. The success of his explosive gasoline engine, forerunner of all succeeding gasoline motor-car engines, was the incentive to inventors to perfect the steam-engine for use on self-propelled vehicles.
Unlike a locomotive, the automobile must be light, must be able to carry power or fuel enough to drive it a long distance, and yet must be almost automatic in its workings. All of these things the modern motor car accomplishes, but the struggle to make the machinery more efficient still continues.
The three kinds of power used to run automobiles are steam, electricity, and gasoline, taken in the order of application. The steam-engines in motor-cars are not very different from the engines used to run locomotives, factory machinery, or street-rollers, but they are much lighter and, of course, smaller—very much smaller in proportion to the power they produce. It will be seen how compact and efficient these little steam plants are when a ten-horse-power engine, boiler, water-tank, and gasoline reservoir holding enough to drive the machine one hundred miles, are stored in a carriage with a wheel-base of less than seven feet and a width of five feet, and still leave ample room for four passengers.
It is the use of gasoline for fuel that makes all this possible. Gasoline, being a very volatile liquid, turns into a highly inflammable gas when heated and mixed with the oxygen in the air. A tank holding from twenty to forty gallons of gasoline is connected, through an automatic regulator which controls the flow of oil, to a burner under the boiler. The burner allows the oil, which turns into gas on coming in contact with its hot surface, to escape through a multitude of small openings and mix with the air, which is supplied from beneath. The openings are so many and so close together that the whole surface is practically one solid sheet of very hot blue flame. In getting up steam a separate blaze or flame of alcohol or gasoline is made, which heats the steel or iron with which the fuel-oil comes in contact until it is sufficiently hot to turn the oil to gas, after which the burner works automatically. A hand air-pump or one automatically operated by the engine maintains sufficient air pressure in the fuel-tank to keep a constant flow.
Most steam automobile boilers are of the water-tube variety—that is, water to be turned into steam is carried through the flames in pipes, instead of the heat in pipes through the water, as in the ordinary flue boilers. Compactness, quick-heating, and strength are the characteristics of motor-car boilers. Some of the boilers are less than twenty inches high and of the same diameter, and yet are capable of generating seven and one-half horse-power at a high steam pressure (150 to 200 pounds). In these boilers the heat is made to play directly on a great many tubes, and a full head of steam is generated in a few minutes. As the steam pressure increases, a regulator that shuts off the supply of gasoline is operated automatically, and so the pressure is maintained.
The water from which the steam is made is also fed automatically into the boiler, when the engine is in motion, by a pump worked by the engine piston. A hand-pump is also supplied by which the driver can keep the proper amount when the machine is still or in case of a breakdown. A water-gauge in plain sight keeps the driver informed at all times as to the amount of water in the boiler. From the boiler the steam goes through the throttle-valve—the handle of which is by the driver's side—direct to the engine, and there expands, pushes the piston up and down, and by means of a crank on the axle does its work.
The engines of modern automobiles are marvels of compactness—so compact, indeed, that a seven-horse-power engine occupies much less space than an ordinary barrel. The steam, after being used, is admitted to a coil of pipes cooled by the breeze caused by the motion of the vehicle, and so condensed into water and returned to the tank. The engine is started, stopped, slowed, and sped by the cutting off or admission of the steam through the throttle-valve. It is reversed by means of the same mechanism used on locomotives—the link-motion and reversing-lever, by which the direction of the steam is reversed and the engine made to run the other way.
After doing its work the steam is made to circulate round the cylinder (or cylinders, if there are more than one), keeping it extra hot—"superheated"; and thereafter it is made to perform a like duty to the boiler-feed water, before it is allowed to escape.
All steam-propelled automobiles, from the light steam runabout to the clumsy steam roller, are worked practically as described. Some machines are worked by compound engines, which simply use the power of expansion still left in the steam in a second larger cylinder after it has worked the first, in which case every ounce of power is extracted from the vapour.
The automobile builders have a problem that troubles locomotive builders very little—that is, compensating the difference between the speeds of the two driving-wheels when turning corners. Just as the inside man of a military company takes short steps when turning and the outside man takes long ones, so the inside wheel of a vehicle turns slowly while the outside wheel revolves quickly when rounding a corner. As most automobiles are propelled by power applied to the rear axle, to which the wheels are fixed, it is manifest that unless some device were made to correct the fault one wheel would have to slide while the other revolved. This difficulty has been overcome by cutting the axle in two and placing between the ends a series of gears which permit the two wheels to revolve at different speeds and also apply the power to both alike. This device is called a compensating gear, and is worked out in various ways by the different builders.
The locomotive builder accomplishes the same thing by making his wheels larger on the outside, so that in turning the wide curves of the railroad the whole machine slides to the inside, bringing to bear the large diameter of the outer wheel and the small diameter of the inner, the wheels being fixed to a solid axle.
The steam machine can always be distinguished by the thin stream of white vapour that escapes from the rear or underneath while it is in motion and also, as a rule, when it is at rest.
The motor of a steam vehicle always stops when the machine is not moving, which is another distinguishing feature, as the gasoline motors run continually, or at least unless the car is left standing for a long time.
As the owners of different makes of bicycles formerly wrangled over the merits of their respective machines, so now motor-car owners discuss the value of the different powers—steam, gasoline, and electricity.
Though steam was the propelling force of the earliest automobiles, and the power best understood, it was the perfection of the gasoline motor that revived the interest in self-propelled vehicles and set the inventors to work.
A gasoline motor is somewhat like a gun—the explosion of the gas in the motor-cylinder pushes the piston (which may be likened to the projectile), and the power thus generated turns a crank and drives the wheels.
The gasoline motor is the lightest power-generator that has yet been discovered, and it is this characteristic that makes it particularly valuable to propel automobiles. Santos-Dumont's success in aerial navigation is due largely to the gasoline motor, which generated great power in proportion to its weight.
A gasoline motor works by a series of explosions, which make the noise that is now heard on every hand. From the gasoline tank, which is always of sufficient capacity for a good long run, a pipe is connected with a device called the carbureter. This is really a gas machine, for it turns the liquid oil into gas, this being done by turning it into fine spray and mixing it with pure air. The gasoline vapour thus formed is highly inflammable, and if lighted in a closed space will explode. It is the explosive power that is made to do the work, and it is a series of small gun-fires that make the gasoline motor-car go.
All this sounds simple enough, but a great many things must be considered that make the construction of a successful working motor a difficult problem.
In the first place, the carbureter, which turns the oil into gas, must work automatically, the proper amount of oil being fed into the machine and the exact proportion of air admitted for the successful mixture. Then the gas must be admitted to the cylinders in just the right quantity for the work to be done. This is usually regulated automatically, and can also be controlled directly by the driver. Since the explosion of gas in the cylinder drives the piston out only, and not, as in the case of the steam-engine, back and forward, some provision must be made to complete the cycle, to bring back the piston, exhaust the burned gas, and refill the cylinder with a new charge.
In the steam-engine the piston is forced backward and forward by the expansive power of the steam, the vapour being admitted alternately to the forward and rear ends of the cylinder. The piston of the gasoline engine, however, working by the force of exploded gas, produces power when moving in one direction only—the piston-head is pushed out by the force of the explosion, just as the plunger of a bicycle pump is sometimes forced out by the pressure of air behind it. The piston is connected with the engine-crank and revolves the shaft, which is in turn connected with the driving-wheels. The movement of the piston in the cylinder performs four functions: first, the downward stroke, the result of the explosion of gas, produces the power; second, the returning up-stroke pushes out the burned gas; third, the next down-stroke sucks in a fresh supply of gas, which (fourth) is compressed by the following-up movement and is ready for the next explosion. This is called a two-cycle motor, because two complete revolutions are necessary to accomplish all the operations. Many machines are fitted with heavy fly-wheels, the swift revolution of which carries the impetus of the power stroke through the other three operations.
To keep a practically continuous forward movement on the driving-shaft, many motors are made with four cylinders, the piston of each being connected with the crank-shaft at a different angle, and each cylinder doing a different part of the work; for example, while No. 1 cylinder is doing the work from the force of the explosion, No. 2 is compressing, No. 3 is getting a fresh supply of gas, and No. 4 is cleaning out waste gas. A four-cylinder motor is practically putting forth power continuously, since one of the four pistons is always at work.
While this takes long to describe, the motion is faster than the eye can follow, and the "phut, phut" noise of the exhaust sounds like the tattoo of a drum. Almost every gasoline motor vehicle carries its own electric plant, either a set of batteries or more commonly a little magneto dynamo, which is run by the shaft of the motor. Electricity is used to make the spark that explodes the gas at just the right moment in the cylinders. All this is automatic, though sometimes the driver has to resort to the persuasive qualities of a monkey-wrench and an oil-can.
The exploding gas creates great heat, and unless something is done to cool the cylinders they get so hot that the gas is ignited by the heat of the metal. Some motors are cooled by a stream of water which, flowing round the cylinders and through coils of pipe, is blown upon by the breeze made by the movement of the vehicle. Others are kept cool by a revolving fan geared to the driving-shaft, which blows on the cylinders; while still others—small motors used on motor bicycles, generally—have wide ridges or projections on the outside of the cylinders to catch the wind as the machine rushes along.
The inventors of the gasoline motor vehicles had many difficulties to overcome that did not trouble those who had to deal with steam. For instance, the gasoline motor cannot be started as easily as a steam-engine. It is necessary to make the driving-shaft revolve a few times by hand in order to start the cylinders working in their proper order. Therefore, the motor of a gasoline machine goes all the time, even when the vehicle is at rest. Friction clutches are used by which the driving-shaft and the axles can be connected or disconnected at the will of the driver, so that the vehicle can stand while the motor is running; friction clutches are used also to throw in gears of different sizes to increase or decrease the speed of the vehicle, as well as to drive backward.
The early gasoline automobiles sounded, when moving, like an artillery company coming full tilt down a badly paved street. The exhausted gas coughed resoundingly, the gears groaned and shrieked loudly when improperly lubricated, and the whole machine rattled like a runaway tin-peddler. Ingenious mufflers have subdued the sputtering exhaust, the gears are made to run in oil or are so carefully cut as to mesh perfectly, rubber tires deaden the pounding of the wheels, and carefully designed frames take up the jar.
Steam and gasoline vehicles can be used to travel long distances from the cities, for water can be had and gasoline bought almost anywhere; but electric automobiles, driven by the third of the three powers used for self-propelled vehicles, must keep within easy reach of the charging stations.
Just as the perfection of the gasoline motor spurred on the inventors to adapt the steam-engine for use in automobiles, so the inventors of the storage battery, which is the heart of an electric carriage, were stirred up to make electric propulsion practical.
The storage battery of an electric vehicle is practically a tank that holds electricity; the electrical energy of the dynamo is transformed into chemical energy in the batteries, which in turn is changed into electrical energy again and used to run the motors.
Electric automobiles are the most simple of all the self-propelled vehicles. The current stored in the batteries is simply turned off and on the motors, or the pressure reduced by means of resistance which obstructs the flow, and therefore the power, of the current. To reverse, it is only necessary to change the direction of the current's flow; and in order to stop, the connection between motor and battery is broken by a switch.
Electricity is the ideal power for automobiles. Being clean and easily controlled, it seems just the thing; but it is expensive, and sometimes hard to get. No satisfactory substitute has been found for it, however, in the larger cities, and it may be that creative or "primary" batteries both cheap and effective will be invented and will do away with the one objection to electricity for automobiles.
The astonishing things of to-day are the commonplaces of to-morrow, and so the achievements of automobile builders as here set down may be greatly surpassed by the time this appears in print.
The sensations of the locomotive engineer, who feels his great machine strain forward over the smooth steel rails, are as nothing to the almost numbing sensations of the automobile driver who covered space at the rate of eighty-eight miles an hour on the road between Paris and Madrid: he felt every inequality in the road, every grade along the way, and each curve, each shadow, was a menace that required the greatest nerve and skill. Locomotive driving at a hundred miles an hour is but mild exhilaration as compared to the feelings of the motor-car driver who travels at fifty miles an hour on the public highway.
Gigantic motor trucks carrying tons of freight twist in and out through crowded streets, controlled by one man more easily than a driver guides a spirited horse on a country road.
Frail motor bicycles dash round the platter-like curves of cycle tracks at railroad speed, and climb hills while the riders sit at ease with feet on coasters.
An electric motor-car wends the streets of New York every day with thirty-five or forty sightseers on its broad back, while a groom in whipcord blows an incongruous coaching-horn in the rear.
Motor plows, motor ambulances, motor stages, delivery wagons, street-cars without tracks, pleasure vehicles, and even baby carriages, are to be seen everywhere.
In 1845, motor vehicles were forbidden the streets for the sake of the horses; in 1903, the horses are being crowded off by the motor-cars. The motor is the more economical—it is the survival of the fittest.
In 1807, the first practical steamboat puffed slowly up the Hudson, while the people ranged along the banks gazed in wonder. Even the grim walls of the Palisades must have been surprised at the strange intruder. Robert Fulton's Clermont was the forerunner of the fleets upon fleets of power-driven craft that have stemmed the currents of a thousand streams and parted the waves of many seas.
The Clermont took several days to go from New York to Albany, and the trip was the wonder of that time.
During the summer of 1902 a long, slim, white craft, with a single brass smokestack and a low deck-house, went gliding up the Hudson with a kind of crouching motion that suggested a cat ready to spring. On her deck several men were standing behind the pilot-house with stop-watches in their hands. The little craft seemed alive under their feet and quivered with eagerness to be off. The passenger boats going in the same direction were passed in a twinkling, and the tugs and sailing vessels seemed to dwindle as houses and trees seem to shrink when viewed from the rear platform of a fast train.
Two posts, painted white and in line with each other—one almost at the river's edge, the other 150 feet back—marked the starting-line of a measured mile, and were eagerly watched by the men aboard the yacht. She sped toward the starting-line as a sprinter dashes for the tape; almost instantly the two posts were in line, the men with watches cried "Time!" and the race was on. Then began such a struggle with Father Time as was never before seen; the wind roared in the ears of the passengers and snatched their words away almost before their lips had formed them; the water, a foam-flecked streak, dashed away from the gleaming white sides as if in terror. As the wonderful craft sped on she seemed to settle down to her work as a good horse finds himself and gets into his stride. Faster and faster she went, while the speed of her going swept off the black flume of smoke from her stack and trailed it behind, a dense, low-lying shadow.
"Look!" shouted one of the men into another's ear, and raised his arm to point. "We're beating the train!"
Sure enough, a passenger train running along the river's edge, the wheels spinning round, the locomotive throwing out clouds of smoke, was dropping behind. The train was being beaten by the boat. Quivering, throbbing with the tremendous effort, she dashed on, the water climbing her sides and lashing to spume at her stern.
"Time!" shouted several together, as the second pair of posts came in line, marking the finish of the mile. The word was passed to the frantically struggling firemen and engineers below, while those on deck compared watches.
"One minute and thirty-two seconds," said one.
"Right," answered the others.
Then, as the wonderful yacht Arrow gradually slowed down, they tried to realise the speed and to accustom themselves to the fact that they had made the fastest mile on record on water.
And so the Arrow, moving at the rate of forty-six miles an hour, followed the course of her ancestress, the Clermont, when she made her first long trip almost a hundred years before.
The Clermont was the first practical steamboat, and the Arrow the fastest, and so both were record-breakers. While there are not many points of resemblance between the first and the fastest boat, one is clearly the outgrowth of the other, but so vastly improved is the modern craft that it is hard to even trace its ancestry. The little Arrow is a screw-driven vessel, and her reciprocating engines—that is, engines operated by the pulling and pushing power of the steam-driven pistons in cylinders—developed the power of 4,000 horses, equal to 32,000 men, when making her record-breaking run. All this enormous power was used to produce speed, there being practically no room left in the little 130-foot hull for anything but engines and boilers.
There is little difference, except in detail, between the Arrow's machinery and an ordinary propeller tugboat. Her hull is very light for its strength, and it was so built as to slip easily through the water. She has twin engines, each operating its own shaft and propeller. These are quadruple expansion. The steam, instead of being allowed to escape after doing its work in the first cylinder, is turned into a larger one and then successively into two more, so that all of its expansive power is used. After passing through the four cylinders, the steam is condensed into water again by turning it into pipes around which circulates the cool water in which the vessel floats. The steam thus condensed to water is heated and pumped into the boiler, to be turned into steam, so the water has to do its work many times. All this saves weight and, therefore, power, for the lighter a vessel is the more easily she can be driven. The boilers save weight also by producing steam at the enormous pressure of 400 pounds to the square inch. Steadily maintained pressure means power; the greater the pressure the more the power. It was the inventive skill of Charles D. Mosher, who has built many fast yachts, that enabled him to build engines and boilers of great power in proportion to their weight. It was the ability of the inventor to build boilers and engines of 4,000 horse-power compact and light enough to be carried in a vessel 130 feet long, of 12 feet 6 inches breadth, and 3 feet 6 inches depth, that made it possible for the Arrow to go a mile in one minute and thirty-two seconds. The speed of the wonderful little American boat, however, was not the result of any new invention, but was due to the perfection of old methods.
In England, about five years before the Arrow's achievement, a little torpedo-boat, scarcely bigger than a launch, set the whole world talking by travelling at the rate of thirty-nine and three-fourths miles an hour. The little craft seemed to disappear in the white smother of her wake, and those who watched the speed trial marvelled at the railroad speed she made. The Turbina—for that was the little record-breaker's name—was propelled by a new kind of engine, and her speed was all the more remarkable on that account. C.A. Parsons, the inventor of the engine, worked out the idea that inventors have been studying for a long time—since 1629, in fact—that is, the rotary principle, or the rolling movement without the up-and-down driving mechanism of the piston.
The Turbina was driven by a number of steam-turbines that worked a good deal like the water-turbines that use the power of Niagara. Just as a water-wheel is driven by the weight or force of the water striking the blades or paddles of the wheel, so the force of the many jets of steam striking against the little wings makes the wheels of the steam-turbines revolve. If you take a card that has been cut to a circular shape and cut the edges so that little wings will be made, then blow on this winged edge, the card will revolve with a buzz; the Parsons steam-turbine works in the same way. A shaft bearing a number of steel disks or wheels, each having many wings set at an angle like the blades of a propeller, is enclosed by a drumlike casing. The disks at one end of the shaft are smaller than those at the other; the steam enters at the small end in a circle of jets that blow against the wings and set them and the whole shaft whirling. After passing the first disk and its little vanes, the steam goes through the holes of an intervening fixed partition that deflects it so that it blows afresh on the second, and so on to the third and fourth, blowing upon a succession of wheels, each set larger than the preceding one. Each of Parsons's steam-turbine engines is a series of turbines put in a steel casing, so that they use every ounce of the expansive power of the steam.
It will be noticed that the little wind-turbine that you blow with your breath spins very rapidly; so, too, do the wheels spun by the steamy breath of the boilers, and Mr. Parsons found that the propeller fastened to the shaft of his engine revolved so fast that a vacuum was formed around the blades, and its work was not half done. So he lengthened his shaft and put three propellers on it, reducing the speed, and allowing all of the blades to catch the water strongly.
The Turbina, speeding like an express train, glided like a ghost over the water; the smoke poured from her stack and the cleft wave foamed at her prow, but there was little else to remind her inventor that 2,300 horse-power was being expended to drive her. There was no jar, no shock, no thumping of cylinders and pounding of rapidly revolving cranks; the motion of the engine was rotary, and the propeller shafts, spinning at 2,000 revolutions per minute, made no more vibration than a windmill whirling in the breeze.
To stop the Turbina was an easy matter; Mr. Parsons had only to turn off the steam. But to make the vessel go backward another set of turbines was necessary, built to run the other way, and working on the same shaft. To reverse the direction, the steam was shut off the engines which revolved from right to left and turned on those designed to run backward, or from left to right. One set of the turbines revolved the propellers so that they pushed, and the other set, turning them the other way, pulled the vessel backward—one set revolving in a vacuum and doing no work, while the other supplied the power.
The Parsons turbine-engines have been used to propel torpedo-boats, fast yachts, and vessels built to carry passengers across the English Channel, and recently it has been reported that two new transatlantic Cunarders are to be equipped with them.
A few years after the Pilgrims sailed for the land of freedom in the tiny Mayflower a man named Branca built a steam-turbine that worked in a crude way on the same principle as Parsons's modern giant. The pictures of this first steam-turbine show the head and shoulders of a bronze man set over the flaming brands of a wood fire; his metallic lungs are evidently filled with water, for a jet of steam spurts from his mouth and blows against the paddles of a horizontal turbine wheel, which, revolving, sets in motion some crude machinery.
There is nothing picturesque about the steel-tube lungs of the boilers used by Parsons in the Turbina and the later boats built by him, and plain steel or copper pipes convey the steam to the whirling blades of the enclosed turbine wheels, but enormous power has been generated and marvellous speed gained. In the modern turbine a glowing coal fire, kept intensely hot by an artificial draft, has taken the place of the blazing sticks; the coils of steel tubes carrying the boiling water surrounded by flame replace the bronze-figure boiler, and the whirling, tightly jacketed turbine wheels, that use every ounce of pressure and save all the steam, to be condensed to water and used over again, have grown out of the crude machine invented by Branca.
As the engines of the Arrow are but perfected copies of the engine that drove the Clermont, so the power of the Turbina is derived from steam-motors that work on the same principle as the engine built by Branca in 1629, and his steam-turbine following the same old, old, ages old idea of the moss-covered, splashing, tireless water-wheel.