Chapter XIII: Introduction (6)

It is within the possibilities, however, that some other birds have even surpassed this speed. The falcon, for example, is probably a swifter bird than the pigeon, at least for short distances. Some one indeed has credited the hawks with a speed of one hundred and fifty miles an hour. But this, I feel sure, is a great exaggeration. I once saw a hen harrier pursue a prairie-chicken, without seeming to gain appreciably for a long distance; yet the prairie-chicken is by no means among the speediest of birds. Many of our ducks, for example, quite outclass it; indeed I should be disposed to admit that the teal or the canvasback at full speed might give the automobile a race.

There is, to be sure, one way in which the bird might get the better of a machine, thanks to its capacity to rise to a height. This would be by taking a sloping course downward. The little shore-lark often gives an exhibition of the possibilities open to the bird in this direction. After rising to a cloudlike height it soars about for a time singing, then suddenly sweeps downward, and, closing its wings, launches itself directly toward the earth, falling with meteoric speed till it almost reaches the surface, when it makes a parachute of its wings and swoops away in safety. During this performance the little lark is, I veritably believe, the swiftest-moving animate thing in all the world. But there is a reason why the bird could not increase its speed indefinitely by imitating the lark's feat in a modified form, and this is the obstacle of atmospheric pressure. Air moving at the rate of sixty feet a second constitutes a serious storm; at ninety feet it becomes a tornado, and at one hundred and fifty feet it is a tornado at its worst--a storm that tears up trees and overthrows houses, and against which no man can stand any more than that he could breast the current of Niagara. Now, of course, it is all one whether the air moves at this rate against you or whether you move at a corresponding rate against the air--action and reaction being equal. Therefore a very serious check is put upon the bird's flight; and it is this consideration which makes it seem doubtful whether any bird, except when aided by a strong wind, can attain such speeds as have been suggested.

Of course, atmospheric pressure affects the automobile no less than the bird. In record-breaking speed tests of the automobile, machine and driver are in effect subjected to the influence of a veritable tornado. Theoretically it seems almost incredible that any power could drive a ton of metal against the air at such a speed; practically we see the feat accomplished. But the automobilist has tales to tell of the power of the wind against his face that are easily credible. Even at ordinary speed in a touring-car, as most of us can testify, the wind blows a gale, veritably forcing tears from the eyes of the novice and blowing them back over his ears. To modify the antagonism of the wind, the constructors of racing motor cars adopt a model suggested originally by the body of a bird or of a fish, and long since made familiar by the shipbuilder.

A MIRACULOUS TRANSFORMATION OF ENERGY

Most of the automobiles, as everybody is aware, are propelled by gasoline engines. This is not their least wonderful feature. To the ordinary observer it seems quite incredible that a little whiff of air mixed with the fumes of a few drops of gasoline should produce a power that can drive pistons with such force as to throw forward what is virtually a bullet weighing more than a ton.

The power that propels this amazing projectile consisted in the aggregate of a few cubic feet of gaseous vapors. The forward motion of the piston sucked a whiff of the gasoline vapor and air into the cylinder; the backward motion of the piston compressed this gas; an electric spark ignited it; the heat of the electric spark enabled the gasoline molecules to unite with the oxygen molecules with explosive suddenness; the conflagration thus started spread instantly to other parts of the compressed gas; the myriad particles of the gas rebounding from one another at inconceivable speed, pressed with the aggregate power of multitudes upon the cylinder, and drove it back with terrific force; then an escape valve opened; the return thrust of the piston drove out the exploded gas, and one revolution of the engine was complete.

Over and over again this cycle was repeated; each revolution requiring for its performance but a bare fraction of the time required to describe it. The thing is simple enough in practice, but it is a marvelous mechanism when you stop to think of it. That such power should be latent in a seemingly harmless whiff of gas is one of Nature's miracles. And that man should have constructed an engine so nicely adjusted in all its parts as to utilize this power is little less than a miracle of mechanics.

A word should be said about another interesting mechanism that pertains not indeed to the speed of the automobile, but to an accurate record of that speed. That is an electrical timing-device with which absolute accuracy of timing is assured. A moment's reflection will show that it would be quite impossible to time the automobile moving at record speed by the old stop-watch method. The nervous impulse through which the mandate of the brain is conveyed to the hand, and thus made to operate on the stop-watch, travels along the nerve of the arm at the rate of not much more than a hundred feet a second. The delay thus involved, added to the time required for the brain itself to act on the message from the eye, is distinctly appreciable, and every one is aware that individuals differ as to their reaction time.

The practical result, therefore, is that timers are often at variance to the extent of as much as two-fifths of a second. Now in two-fifths of a second, as we have seen, the record motor car covers a distance of over 77 feet. Obviously such latitude in measurement could not be permitted. Hence an electric device has been elaborated which tests the speed with absolute accuracy, recording it automatically on a strip of tape. Therefore the fractional seconds are now stated in hundredths instead of in mere quarters or fifths, and we may be confident--as we could not always be regarding the old-time records--that the different fractions of a second represent an actual difference of speed.

It may be of interest to make a further comparison between the speed of the record automobile and the fastest speed ever attained by a railway locomotive--namely, a mile in thirty seconds. The gap is by no means an insignificant one. A mile in thirty seconds means 176 feet a second. This would allow the champion automobile a lead of over seventeen feet each second; and at the end of a mile the locomotive would be distanced by 1040 feet. It is interesting to visualize the procession that the automobile would leave behind if placed in competition with the various kinds of champions whose feats have been mentioned. As the automobile crossed the line the locomotive would be almost one-fifth of a mile in the rear; 1,900 feet farther back would come the homing pigeon; after a long gap Salvator, the first runner, would come straggling along, having covered little more than one-fourth of a mile; Lou Dillon would be just beyond her first fifth of a mile; the fastest cyclist would be placed between the racer and the trotter; while Hutchins, the swiftest runner at the distance, would have gone only 240 yards from the tape.

For distances greater than two miles, the locomotive record has not as yet been surpassed by the automobile. A locomotive on the Plant system, for example, is credited with a run of five miles in two and one-half minutes (in 1901). But, of course, there is nothing except the mere matter of speed that makes the locomotive engineer's performance comparable to that of the chauffeur. The engineer is driving a machine that runs on a fixed track. He has to do little more than keep up steam and open the throttle. The chauffeur must pick his course, for at any moment a soft spot in the sand may tend to deflect him. How appalling may be the result of a slight deflection with a machine going at great speed has been illustrated by the tragic accidents that have marred the success of many important racing-events, and have led to the oft-repeated question as to whether, after all, such speed tests are worth while. It is a question that everyone must answer for himself. The dangers are obvious; but, on the other hand, most athletic competitions have an element of danger; and enthusiasts may well contend that speed tests make for progress, and are largely responsible for the great mechanical improvement that is in evidence.

VI

THE DEVELOPMENT OF ELECTRIC RAILWAYS

The United States has been preëminent in the development of street railways of all kinds, from the earliest type of horse-car to the modern city and interurban electric cars. Nevertheless, very few of the great general underlying principles upon which these numerous inventions are based have been discovered upon this side of the Atlantic. American inventors have simply excelled in applying the known general principles to practical mechanisms. But although the American inventors have largely monopolized this field of progress, the names of many Europeans also are connected with it. In several instances these foreign inventors, as naturalized American citizens, have done their work in America, being attracted to this country by the exceptional opportunities offered.

In recent years the city of New York has not shown conspicuous activity in adopting innovations and improvements on its street-railway lines. Nevertheless, New York was the first city in the world to have a passenger street railway. This, built in the early 20's, and running along Fourth Avenue, had rails made of straps of iron laid on stone ties. On this primitive line an omnibus horse-car, called the _John Mason_, was operated. This car was built on the lines of the early railway carriages, having three compartments, with doors opening at the sides. It was, in short, an early type of the side-door cars now used so universally on all European railways. The driver's seat was high in the air as in the case of the ordinary omnibus, and there were seats on the top for passengers.

For several years this primitive road remained the only street railway in existence. But it did not prove a particularly good business venture, and for some time capitalists were wary of investing their money for the construction of other lines. Twenty years later, however, a somewhat similar road, considerably improved, was built on Sixth Avenue. This proved to be a financial success; other lines were soon constructed, and the era of street railways opened.

The great advantage of these horse-car lines over the system of omnibuses then in use lay in the fact that greater loads could be hauled with the same expenditure of horse-power, regardless of weather conditions. The contrast in this respect was particularly marked in American cities where the streets, almost without exception, were badly paved.

By 1850, several cities in the United States had installed street railways; and by 1870 over a hundred lines had been built. Between 1870 and 1890 this number had been increased to over seven hundred, not taking into account the numerous extensions that had been made to many of the older lines.

CABLE SYSTEMS

Even in the early days of street-railway construction the extravagance of the method of horse-power traction was fully appreciated, and the numerous improvements in steam-engines stimulated attempts to adapt the locomotive in some form to city railways. But there were many difficulties in the use of the ordinary, or specially constructed, locomotives in the crowded thoroughfares of the larger cities. It was practically impossible to eliminate their smoke; and their puffing and wheezing, which frightened horses, caused numerous accidents. But even if these defects could be corrected, the locomotive was known to be an expensive form of motive power, when applied to a single short car, carrying at most only a few passengers and making frequent stops, as was necessary in street-car traffic. The inventors, therefore, looked about for other methods of applying steam power. But it was not until 1873 that this idea took the practical form of the cable road, on which single cars could be operated by means of underground cables travelling in slotted tubes, and propelled from a stationary power-plant.

The first practical cable system was made by Andrew S. Hallidie, and his associates, who planned and put into operation the first cable line in San Francisco. It proved to be entirely successful, and was imitated almost immediately in most of the larger cities of the United States, and in some European cities. Within a decade the number of cable railways installed had so reduced the number of horses necessary for operating street-car lines all over the country that there was an appreciable depression in the market prices of such horses.

The importance of this method of transportation is shown in the fact that between the years 1873 and 1890 more than a thousand different patents directly connected with the operation of cable roads were issued by the United States Patent Office. But by 1890 electric traction had become practical, and the issuing of patents for cable lines ceased as abruptly as it had begun. Before the close of the century practically every important cable line in the United States had changed its motive power to electricity. Thus in a brief quarter of a century this method of street-car traction had come into existence, revolutionized all hitherto known methods, and become obsolete.

EARLY SELF-CONTAINED SYSTEMS

In most of the earlier attempts to solve the problem of electrical propulsion the motor vehicles were constructed on a self-contained plan--that is, the power was generated on the locomotive itself, just as in the case of the steam locomotive. As early as 1835 Thomas Davenport, a blacksmith of Brandon, Vermont, constructed such a motor operated by cells, and built a small circular railway in Springfield, Massachusetts, on which he drove this electro-magnetic engine. This miniature railroad was of no practical importance, but it has the distinction of being the pioneer electric road.

Shortly after this, Prof. Moses G. Farmer, a distinguished American inventor and investigator, constructed an electro-magnetic locomotive, which drew a little car, and carried passengers, on a track a foot and a half wide. The locomotive used about fifty Grove cells, which developed a relatively small amount of energy at an enormous cost.

"In 1850-51," says Martin, "Mr. Thomas Hall, of Boston, exhibited a small working-motor on a track forty feet long, at the Mechanics' Charitable Fair in Boston, and while this was a mere toy, and used but a couple of cells of battery, it sufficed to illustrate the principles of a motor or locomotive with a single trial car. About this time (1847) an interesting demonstration was also made with a small working-model, one of the features of which has been most instrumental in the success of the modern electric methods, that of the utilization of the track as part of the return circuit for the current. Doctor Colton, once a famous dentist in New York City, and noted for his early application of laughing-gas in that work, was associated with Mr. Lilly in the construction and operation of a small model locomotive which ran around a circular track. The rails were insulated from each other, each connecting with one pole of the battery. The current from the battery was taken up by the wheels, whence it passed to the magnets, upon whose alternating attraction and repulsion motion depended; then it returned to the other rail, connected the other pole of the battery, and thus completed the circuit necessary for the flow of the current. In like manner in a great majority in use at present, the current passes from one power-house to circuits of one polarity, through the trolley pole to the motor or electro-magnetic propelling system, thence through the wheels to the track, which completes the circuit by being connected to the other pole or side of the dynamo at the power-house. The principles are obviously identical, but it took more than a quarter of a century to develop the proper method of application in all its details.

"The most serious and sustained attempt in the early period to operate a self-sustained vehicle or car--which would correspond with the storage-battery cars--was that due to Prof. C. C. Page, of the Smithsonian Institution. About 1850, Professor Page devoted considerable time to the development of electric engines or motors, in which the reciprocating action of a system of magnets and solenoids or armatures was applied by crank-shafts to driving a fly-wheel, to which rotary motion was thus imparted. This reciprocal motion, as in steam-engines, was one of the prevailing features of the early electric-motor work in this country and in Europe; but it was not long before its general inapplicability was realized, and it was abandoned for the simpler and more direct rotation of the armature before or between the poles of electro-magnets.

"On April 29, 1857, with an electric locomotive on which he had installed a large reciprocating motor developing over 16 horse-power, Professor Page made a trial trip along the track of the Washington and Baltimore Railroad, starting from Washington. In order to obtain current for energization, the motor was equipped with one hundred cells of Grove nitric-acid battery, each having as one element a platinum plate eleven inches square, dipped in the acid. Bladensburg, a distance of about five and one-quarter miles, was reached in thirty-nine minutes, and a maximum speed of nineteen miles an hour was attained; the entire trip to and from Bladensburg occupied one hour and fifty-eight minutes. But many disasters happened to the batteries. Some of the cells cracked wide open, and jolts due to inequalities of track threw the batteries out of working order. These experiments must have been extremely costly, and no little discouragement among people in general attended this failure; but Professor Page was not daunted, and for some years continued his work on electric motors, displaying great ingenuity, but not able, apparently, to give up the reciprocating principle."

The invention of the commercial dynamo, shortly after the middle of the nineteenth century, opened the era of practical electric-railway construction on both sides of the Atlantic. The German experimenters, Siemens and Halske, and later the American, Stephen D. Field, paved the way by numerous experiments and discoveries. It was not until about 1880, however, that the idea of using a third rail for transmitting the current was conceived. Hitherto, most of the inventors had attempted to use one rail as a receiving part of the circuit to the motor, the other rail completing the return part of the circuit. And it was several years after the idea of the third rail had germinated before the attempts to utilize one of the traction rails for conveying the current was abandoned.

THE EDISON ELECTRIC LOCOMOTIVE

In 1880, Mr. Thomas A. Edison, at Menlo Park, New Jersey, perfected a series of electric-railway motors and locomotives that were actually employed in hauling freight and passengers. The following year Mr. Edison made a contract with Mr. Henry Villard, which stipulated that the inventor was to construct an electric railway at least two miles and a half in length, which was to be equipped with two locomotives and three cars, one locomotive for freight and one for passengers, the passenger locomotive to have a capacity of sixty miles an hour. It was agreed that if the experiment with this railway proved successful Mr. Villard was to reimburse Mr. Edison for the actual outlay, and to install at least fifty miles of electric road in the wheat regions of the Northwest.

The electric locomotives built by Mr. Edison were constructed along the usual lines of steam locomotives, with cab, headlight, and cowcatcher, the motive power being applied from the motors to the axle by means of friction pulleys. This method was soon abandoned, as the pulleys slipped a great deal before the locomotive actually started. A system of belts which was substituted proved more satisfactory. The current was conveyed to the motor through the track, and was supplied to the road by underground cables connecting from the dynamo-room of Mr. Edison's laboratory. The rails were insulated from the ties by coatings of Japan varnish, and by placing them on pads made of muslin impregnated with tar.

From the very first this road gave promise of success. The tireless genius of Edison was constantly finding and correcting defects, and there was every prospect that in a few months a practical and economical electric railway would be an accomplished fact. Then came the financial crash of the Northern Pacific Railway, involving the fortune of Mr. Villard, and tying the hands of the inventor at Menlo Park for the time being.

The year following, however, Mr. Field and Mr. Edison combined their forces and formed a company for perfecting and constructing electric locomotives and railways. In the same year an electric railway was put in operation at the Chicago Railway Exposition, the chief promoters of this enterprise being Messrs. Field, F. B. Rae, and C. O. Mailloux. In the gallery of the building a circular track, something like a third of a mile in length, was laid, and on this an electric locomotive named _The Judge_ hauled a single car which carried over twenty-six thousand passengers in the month of June. In the autumn of the same year, _The Judge_ was used for hauling passengers on a track at the Louisville Exposition. It was capable of attaining a speed of twelve miles an hour, and its average speed was eight miles. It was twelve feet long over all, weighed something like three tons, and, like Edison's locomotive, was equipped with cowcatcher, headlight, and cab. The current was taken from a surface, or feed rail, by means of bundles of phosphor-bronze wire, so arranged that a good clean contact would be made on each side of the rail whether the car was moving forward or backward.

THIRD RAILS AND TROLLEYS

At the same time an Englishman named Leo Daft, then living in America, was making some important experiments with motors for the purpose of driving machinery, these motors being operated from central power-stations located at distant points. Mr. Daft constructed an electric locomotive, and in November, 1883, constructed what was known as the Saratoga and Mount MacGregor Railroad. This railroad was twelve miles in length and included many steep grades. The locomotive, which hauled a regular passenger-car, received the current from a central rail. The year following Mr. Daft built and equipped a small road on one of the long piers of Coney Island, which carried something like forty thousand passengers in one season. It was an improvement over the Siemens electric railway established in Germany in 1881--which, however, was the first road ever established.

The following year the inventor began the equipment of the Baltimore Union Passenger Railway Company, a line that ran a distance of about two miles and reached an elevation of one hundred and fifty feet above the city of Baltimore. This road was put into regular operation in 1886, and was the second electric street railway in America for carrying on regular passenger service.

The Baltimore Union Railway had several novel and important features, one of them being the equipment of part of the line with an overhead-trolley service, the practical importance of which had been demonstrated shortly before by Van Depoele. The projector, Mr. Daft, also built several other lines in different parts of the country, constantly improving upon his earlier efforts, sometimes using two overhead trolley wires, with two trolley contacts, thus doing away with the use of the track as a means of current supply, or for use as part of the circuit. Although in recent years double overhead trolleys have largely disappeared, some of them are still in use both in America and in Europe.

Van Depoele was a Belgian who had come to America in 1869. Although primarily a cabinet-maker, he had a great liking for the study of electricity, and devoted all his spare time and money to efforts to solve the problem of practical street-car propulsion. In 1883, at the Industrial Exposition at Chicago, he operated a car by electricity, using an overhead-trolley system somewhat similar to Daft's. By 1885, he had made sufficient progress to construct a line one mile long for carrying passengers from the railway station to the Annual Exhibition grounds at Toronto, Canada. On a single track he operated three cars and a motor, carrying an average of ten thousand passengers daily, his train sometimes attaining a speed of thirty miles an hour. For receiving the current he used an underrunning trolley and pole very similar to the form now in common use, this being one of the first instances of employing this particular method of receiving the current. In this system an insulated track was used for returning the current.

Van Depoele's next venture was the equipment of an electric railway at South Bend, Indiana, on which five separate cars were operated at one time--a thing supposed by many to be impossible. The cars of this road were equipped with motors placed under the cars instead of above them, thus saving valuable seating-space. In place of the underrunning trolley and pole, however, the current was taken from the overhead wire by means of a flexible cable. Later Van Depoele invented an underrunning trolley and pole, taking out the original patents. His claims to priority were contested eventually, but they were sustained by the United States courts.

At this time there were at least a score of inventors whose work added something of importance to the solution of the problem of electric traction. But without belittling others, it is probably only justice to say that the work of Frank J. Sprague, a one-time lieutenant in the United States Navy, marks the beginning of the modern era of street railways. In 1888, after a period of struggle and a series of disheartening disasters, Mr. Sprague and his associates opened an electric line for the Union Passenger Railway of Richmond, Va., which "forms a landmark in the history of this industrial development." Over a line of road with grades at that time considered impossible, thirty cars were put into use at the same time, the contract for the equipment calling for its completion in ninety days. The success of this enterprise, when on the opening day more electric cars were operated than in all the rest of America together, settled forever the question of the practicality of electric street railways, as well as many of the questions of the practical application of the current, thanks to Sprague's inventive genius.

This road was an overhead trolley-wire system, with an underrunning trolley held in place by the now-familiar trolley pole. The number of difficulties that had to be solved in perfecting this apparently simple piece of apparatus is shown by the statement of Mr. Sprague that "probably not less than fifty modifications of trolley wheels and poles were used before what is known as the 'universal movement' type was adopted."

In this connection the origin of the word "trolley" is interesting. It seems to have been corrupted from the word "troller" by the workmen of a Kansas City car-line. On this line an overhead wire was used, the travelling carriage taking the current from the wire being known as the "troller." The employees of the road, however, shortly corrupted "troller" into "trolley"; and "trolley" it has remained ever since.

As in the case of Van Depoele, whose perfection of the underrunning trolley was contested legally, Sprague's great contribution to electric traction, the suspension of the motor directly upon the axle, had finally to be sustained by the United States courts. Sprague's method was to hang the motor under the car directly upon the axle, by an extension or solid bearing attached directly to the motor. This plan of constructing the motor, together with numerous other improvements, principally in the direction of lightness, simplicity, and adaptability, soon superseded all pre-existing methods of construction. Thus Van Depoele's method of taking the current from the wire, and Sprague's method of utilizing it in the propulsion of the car, must be regarded as epoch-marking steps in the history of electric traction. Sprague's invention demonstrated the validity of his contention, now universally accepted, that motors should be placed under each car instead of being used on locomotives.

STORAGE-BATTERY SYSTEMS

From the earliest attempts at solving the question of electric traction, efforts were made to produce some form of storage battery whereby the cars might be made independent of a distant generating plant. The advantages of a self-contained vehicle are so obvious that it is not surprising to find the inventors persistent in their attempts at producing practical cars of this type. Such battery cars would not require the dangerous, expensive, and cumbrous system of overhead wires, or the more sightly but also more expensive system of conduits. With such a system of cars the elaborate mains and feeders for bringing the current to the track from the power-house, and for effecting the return circuit, could be dispensed with. Moreover, the independent action of such cars over a system where the power is furnished from a single source, where the stoppage of the current stops every car along the line, is inestimable.

Between the years 1880 and 1883 many storage-battery cars were built and put in service both in European and American cities. Probably the most important one of these lines was that which was built by the Belgian, Mr. E. Julien, in New York city, in 1887-8. On the Fourth Avenue road something like a dozen storage-battery cars were put in operation for a considerable time, and later, improved modifications of these cars were operated in Philadelphia under the direction of Mr. Anthony Rackenzaun, of Vienna. But despite the apparent simplicity of the storage-battery idea, innumerable difficulties were perpetually presenting themselves in its practical application. Despite the disheartening results, however, storage-battery cars were not entirely abandoned in practice until 1903, New York city being the last to surrender, as it had been about the last to adopt them.

But in February, 1910, the storage-battery street car again made its appearance on trial in New York--not the old heavy type of unsatisfactory car, but an entirely new and lighter creation of Thomas A. Edison, who had been striving for years to solve the storage-battery problem. This car, which had been tested on the Orange, New Jersey, street-car line on January 20th, 1910, maintained a speed of fifteen miles an hour in actual practice, and ran a distance of about one hundred and fifty miles without re-charging the batteries.

There are some novel features about the car itself, but the all-important one is the peculiar and novel storage battery which it has taken Mr. Edison some nine years to perfect. In an imperfect form this battery was given a trial in 1903, and much was expected of it because it was not only lighter than the usual form of storage battery, but it promised more permanency because an alkali was used in place of an acid as an electrolyte.

In this battery the positive element, which consisted of nickel oxide interspersed with layers of graphite, was packed in perforated nickel tubes. The negative element was iron oxide, with potassium hydrate as the electrolyte. This battery showed no bad effects from over-charging or from being rapidly discharged, but it was found that the graphite soon became oxidized and interfered with the working of the battery. This defect was corrected by substituting chemically pure nickel for the graphite, but another was soon discovered. Under the pressure of the oxide of nickel the square tubes containing the nickel were frequently injured so that the powdered nickel oxide was sifted down on the pure nickel layers and insulated them.

The only solution of this difficulty seemed to be to pack the nickel in strong round tubes four inches long and about the size of a lead pencil, the sides of the tubes being finely perforated. But the expense of producing such tubes by ordinary methods was prohibitive. A machine was finally invented, however, which made the tubes economically by using spirally wound ribbons of metal, the edges being fastened together during the coiling process. By the use of these tubes the battery was so far perfected that it was given extensive trials in 1908 on electric vehicles; and as these tests proved satisfactory, Mr. Edison began the construction of a specially designed street car equipped with two 5-horse-power 110-volt motors of very light construction. The car weighs complete about five tons, and the batteries are stored under the seats running along each side.

This car was tested continuously for three weeks on one of the New York cross-town lines and performed its work so satisfactorily and economically that the management of the line decided to give the system a permanent trial. The regular daily run of this car averaged something over sixty-six miles, but this by no means exhausted the capacity of the batteries; and it is estimated that it could easily have run at least one-quarter farther without re-charging. The surprising feature of these tests was the low cost of running. The total cost of electric power for the day's run was about thirty cents, or 4.3 mills for each mile. The ordinary New York street car costs on an average about five cents per mile for electrical energy; but on the other hand, the carrying capacity of these cars is almost twice that of the Edison car.

The actual cost of running the car, however, was only one of its many advantages. The fact that no underground conduits have to be laid or overhead wires erected and maintained makes the initial cost of installing the line far less than by any other system. The reduction in the cost of maintenance of the line is also an important item, as it is estimated that the cost of repairs on conduit lines is about $15,000 annually per mile.

But the most convincing proof that Mr. Edison has really produced a practical storage battery car lies in the fact that, after testing his car for three weeks in actual traffic, the managers of the street-car line ordered sixteen similar cars for operation over their road.

MONORAIL SYSTEMS

The introduction of electricity facilitated the construction of monorail systems of roads, which had long been the dream of railroad constructors, since this power could be applied with so much more flexibility. The defects of the parallel rail system are apparent both in construction of the roadbed and the operating of trains. It is almost impossible to lay and maintain the rails in exact parallels, and even more difficult to keep each rail at the proper height at all points. Both these factors enter very largely into the determination of the speed that a train can make over such tracks, any very great variation from the parallel causing derailment, while slight depressions or elevations of either rail cause violent and dangerous rocking of the cars travelling at high speed.

In any monorail system the first of these difficulties, the deviation of the rail from the parallel, is, of course, eliminated; and it is found that on a single rail the elevations and depressions are not serious obstacles. Moreover, the cost of construction of a single-rail track must obviously be less than for a double-rail track, and the power necessary to operate cars over such a track far less. But until the invention of the gyrocar (which is referred to at length in the following chapter) the methods of balancing the car on a single rail presented difficulties which quite offset the advantages of the monorail system. Some of these methods are unique and a few of them are practical in actual operation.

In Germany a suspension monorail system is in operation, the cars being suspended from an overhead track. But obviously such a system, which requires elaborate and expensive steel trestle-work along every fork of the road, is not adapted to the use of long-distance roads except in thickly populated districts. A less expensive and highly satisfactory system is the one invented by Mr. Howard Hansel Tunis and used at the Jamestown Exhibition in 1907.

In this system the wheels, arranged in tandem, have double flanges which keep them on the single-rail track, and the cars are prevented from toppling over by overhead guides. These guides must be supported on a frame-work, but as there is little tendency to sway on a single-rail track, they can be relatively light structures. It is the cost of these frames, however, that practically offsets the low cost of road-bed construction, so that, everything considered, the mere matter of initial cost has no very great advantage over the ordinary double-rail road. But the cost of operating is considerably less than the older type, and this road would undoubtedly come rapidly into popularity but for the fact that such gyrocars as the ones invented in England and Germany are self-sustaining on the rail, doing away with the expensive overhead frame-work construction, and are likely to become practical factors in the problem of transportation.

In 1909 an electric aerial monorail up the Wetterhorn in the Alps was put into operation. On this line a car suspended on two cables, one above the other and without supports except at the upper and lower terminals, rises at an angle of forty-five degrees through a distance of 1,250 feet. There are two sets of these cables, each carrying a car so arranged as to work in alternate directions simultaneously, this counter-balancing effecting a great saving in power. The power-plant is located at the upper end of the ascent, and consists of winding drums actuated by electricity which raise and lower the cars by means of cables. On the cars themselves, therefore, there is no power, but each car is equipped with brakes powerful enough to stop and hold it notwithstanding the steepness of the incline.

There is nothing particularly novel in the principles involved in this aerial road, but it is the first of its kind to be built for passenger traffic. Similar less pretentious roads have been in use for freight transportation for several years. But the success of this road means the building of others on inaccessible mountain inclines where the laying of ordinary roadbeds is out of the question, and the operating of cog roads too expensive.

VII

THE GYROCAR

On the 8th of May, 1907, Mr. Louis Brennan exhibited, at a _soirée_ of the Royal Society in London, a remarkable piece of mechanism, which stirred the imagination of every beholder, and--next morning--as reported by the newspapers, aroused the amazed interest of the world. This invention consists of a car run on a single rail, standing erect like a bicycle when in motion; but, unlike the bicycle, being equally stable when at rest.

It is a car that could cross the gorge of Niagara on a tight-rope, like Blondin himself, but with far greater security; a car that shows many strange properties, seeming to defy not gravitation alone but the simplest laws of motion. For example, if a weight is placed on one edge of the car that side rises higher instead of being lowered.

If you push against the side with your hand, the mysterious creature--you feel that it must be endowed with life--is actually felt to push back as if resenting the affront.

Similarly, if the wind blows against the car, it veers over toward the wind. If the track on which it runs--consisting of an ordinary gas-pipe or of a cable of wire--is curved, even very sharply, the car follows the curve without difficulty, and, in defiance of ordinary laws of motion, actually leans inward as a bicycle rider leans under the same circumstances, instead of being careened outward as one might expect.

A curious mechanism, surely, this new car, with its four wheels set in line, bicycle fashion, running thus steadily. But strangest of all it seemed when it poised and stood perfectly still on its tight-rope, as no Blondin could ever do. As stably poised it stood there as if it had two rails beneath it instead of a single wire; and there was nothing about it to suggest an explanation of the miracle, except that there came from within the car the murmur of whirling wheels.

The mysterious wheels in question would be found, if we could look within the structure of the car, to be two in number, arranged quite close together on each side of the centre of the car. They are two small fly-wheels, in closed cases, revolving in opposite directions, each propelled by an electric motor. These are the wonder-workers. They constitute the two-lobed brain or, if you prefer, the double-chambered heart of the strange organism. All the world has learned to call them gyroscopes. The vehicle that they balance may conveniently be termed a gyrocar--a name that has the sanction of the inventor himself.

Let it be understood once for all that a gyroscope is merely a body whirling about an axis. A top such as every child plays with is a gyroscope; a hoop such as every child rolls is a gyroscope; the wheels of bicycles, carriages, or railway-cars are gyroscopes; and the earth itself, whirling about its axis, is a gyroscope. You can make a gyroscope of your own body if you choose to whirl about, like a ballet-dancer. In a word, the gyroscope is the most common thing imaginable. Indeed, if I wished to startle the reader with a seeming paradox, I might say without transcending the bounds of truth that, in the last analysis, there is probably nothing known to us in the universe but an infinitude of gyroscopes--atoms and molecules at one end of the scale; planets and suns at the other--all are whirling bodies. Still there are gyroscopes and gyroscopes, as we shall see.

GYROSCOPIC ACTION EXPLAINED

Now a word about gyroscopic action. If you have rolled a hoop or spun a top you have unwittingly learned some practical lessons on the subject which, had you possessed Mr. Brennan's imagination and ingenuity, might have enabled you to anticipate him in the invention of the gyrocar. Harking back to the days when you rolled hoops, you will recall that the child who most excelled in the art was the one that could make the hoop go fastest. The hoop itself might be merely a wheel of wire, which would fall over instantly if not in motion; but if given a push it assumed an upright position and maintained it with security, so long as it was impelled forward. It seemed able, so long as it whirled about, to defy the ordinary laws of gravity. A bicycle in motion gives an even more striking illustration of the same phenomenon. And best of all, a spinning-top. Everyone knows how this familiar toy, which topples over instantly when at rest and can in no wise be balanced on its point, rises up triumphant when whirled about, and stands erect, poised in a way that would seem simply miraculous to all of us, had we not all spun tops at an age when the world was so full of wonders that we failed to marvel at any of them.

All these familiar things illustrate one of the principles of gyroscopic action which Mr. Brennan has put to account in developing his wonderful car--the fact, namely, that every revolving body tends to maintain its chief axis in a fixed direction, and resents--if I may be permitted to use this expressive word--having that direction changed. The same principle is illustrated on a stupendous scale by our revolving earth, which maintains the same tilt year after year as it whirls on its great journey, notwithstanding the fact that the sun and the moon are tugging constantly at its protuberant equatorial region in a way that would quickly change its direction if it were not spinning.

But note, please, that whereas the whirling body assumes a certain rigidity in space as regards the direction in which its axle points, the mere translation of the body itself through space in any direction is not interfered with in the least, provided the axle is kept parallel with its original position.

You may test this if you like in a very simple way. Remove one of the wheels of your bicycle, and carry it about the room, holding it by the axle while it is spinning rapidly. You will discover that it requires no more force to carry it when spinning than when at rest, provided you do not attempt to tip it from its plane of rotation, but that if you do attempt so to tip it, the wheel seems positively to resist, exerting a force of which it did not show a trace when at rest. A large top, arranged within the kind of frames or hoops called gimbals, if you can secure such a one, will show you the same phenomenon; it will resist having its axis diverted from the direction it chanced to have when it was set spinning.

If you ask why the spinning wheel exerts this power, it may not be easy to give an answer. The simplest things are hardest to explain. No man knows why and how gravitation acts; no one knows why a body at rest tends always to remain at rest until some force is applied to it; nor why when a body is once in motion it tends always to move on at the same rate of speed until some counter-force stops it. Such are the observed facts; they are facts that underlie all the principles of mechanics; but they are matters of observation, not of explanation or argument. And the fact that a revolving body tends to maintain its axis in a fixed position is a fact of the same category.

So far as we can explain it at all, we may, perhaps, say that the inertia which the matter composing the wheel shares with all other matter is accentuated by the fact that its whirling particles all tend at successive instants to fly in different directions under stress of centrifugal force. At any given instant each individual particle tending to fly off in a particular direction may be likened to a man pulling at a rope in that direction.

If you imagine an infinite number of men circled about a pole to which ropes are attached, and evenly distributed, each one pulling with equal force, it will be clear that the joint effort of the multitude would result in fixing the pole rigidly at the centre. The harder the multitude pulled, so long as they remained evenly distributed about the circle, the more rigid the pole would become. But if, on the other hand, all the men were to stop pulling and slacken the ropes, the pole would at once fall over. The pole, under such circumstances, would represent the axis of the revolving wheel, which acquired increased stability in exact proportion to the increased velocity of its revolutions, and therefore of the increased force with which its particles tend to fly off into space.

But be the explanation what it may, the fact that the axis of a revolving wheel acquires stability and tends to maintain its fixed position in space is indisputable; and it is this fact which determines primarily the action of the little revolving wheels of the gyroscopes that balance Mr. Brennan's car. There are certain very important additional principles involved that I shall refer to in a moment, but first let us glance at the car itself and see how the gyroscopes are arranged. We shall find them fastened within the frame-work of the car, at its longitudinal centre, in such a way that their axles are parallel to the axles of the ordinary car-wheels when the car stands in a normal position. Granted that the gyroscopes are thus transverse and normally horizontal, and at right angles to the track, the exact location of the mechanism within the car is immaterial. But the two gyroscopes must revolve in opposite directions for a reason to be given presently.

The De Witt Clinton engine, with its archaic coaches, represents the earliest type of railway transportation in America. The Gyro-car, two views of which are given, is the working model of a single-rail vehicle exhibited in England by Mr. Louis Brennan in 1907. It is balanced by an ingenious gyroscopic mechanism, which its inventor believes will prove equally successful when applied to vehicles on a commercial scale.]

MR. BRENNAN'S MODEL CAR

The Brennan car as at first exhibited was only a working-model about six feet in length, and the gyroscopes that balanced it were about five inches in diameter. It seems almost incredible that wheels so small should be able to balance a car six feet in length, but it must be understood that these small gyroscopes whirl at the rate of about seven thousand revolutions per minute, and, of course, the gyroscopic force is proportionate to the rate of revolution. If we recall that a light hoop making perhaps fifty or a hundred revolutions per minute acquires a considerable stability, we shall cease to wonder at the rigidity of the axles of the wheels revolving at such enormous speed.

The model car accomplished the feat of carrying a passenger weighing about one hundred and forty pounds across a little valley on a wire cable, a voyage in some respects the most remarkable that any man has thus far been privileged to make. The car has shown that it can go up or down a sharp incline; but this, as a moment's reflection will show, does not involve any change of direction of the gyroscopic axle, and therefore involves only the ordinary laws of mechanics. It is all one to the gyroscope whether the car moves on the level or up or down hill, so long as it moves straight ahead.

Nor do the gyroscopes interfere in the least with the turning of the car in passing round a curve, when the two of them are linked together, as Mr. Brennan links them, so that any lateral change in the axis of one is balanced by an opposite change of the axis of the other. With the single gyroscope, such as Mr. Brennan used when he first began his experiments, the car encounters difficulties at curves in the track.

But before we can understand how the two gyroscopes balance each other in such a way as to make the Brennan car lean in while passing about a curve, we must investigate more fully the action of the individual gyroscopes. I have already said that there is another principle involved as supplementary to the principle of the fixed axis; this we must now investigate.

Perhaps it would be fairer to say that what we have to consider is not a new principle but a complication as to the application of the principle of gyroscopic action already put forward. In any event there is an elementary fact about the gyroscope that I have not yet stated. It is this: in order that the gyroscope may exercise its fundamental property of holding its axis fixed, it must have that axis so adjusted that it is free to oscillate or wabble. That sounds distinctly paradoxical, but it is a very essential fact. If Mr. Brennan had merely fixed two wheels rigidly in the frame of his car, they would have had no appreciable effect in balancing it. Had nothing more than that been necessary, some one would have invented a gyrocar long ago. But very much more than that was necessary, as we shall see.

The complication of which I am speaking is illustrated by the action of the simplest top, which likewise owes its stability to its wabble. Your top does not rise merely because it spins, but because it wabbles as it spins--wabbling being the familiar word for what the machinist calls "precession." A freely spinning top, if in equilibrium, has no inherency to rise up against gravitation, as your top may have led you to suppose. Your top rises because it is not spinning freely in equilibrium, its action being interfered with by the friction of the point on which it rests; it is seeking a position of equilibrium, which, owing to the location of its centre of gravity, will be found when its spindle is erect. But a top supported at both ends and properly balanced, does not tend to rise but only to maintain its position.

HOW THE BRENNAN GYROSCOPES WORK