An Attempt to Deliver by Them Goods from Department Stores.

A HORSE'S WORK AT A CENT AN HOUR

Gas Produced by Petroleum Will Be the Motive Power—The Engine to be Only Eighteen Inches High.

An attempt is soon to be made to prove to the owners of the large retail dry goods stores in this city that mechanical power is cheaper and more efficient in the delivery of packages than wagons drawn by horses.

The engines for these horseless wagons are the same as those used in the carriages which recently bore off the prizes in the race from Paris to Bordeaux.  They are constructed somewhat on the pattern of an ordinary gas engine, with numerous changes and rearrangements of the working parts so as to make them of the smallest possible bulk.

The delivery vans or wagons will not be outwardly different in appearance from those at present in use, except that there will be no horses in front, and that the steering, instead of being performed by reins, will be effected by means of a long arm or wheel, the perpendicular rod from which will be attached to the lock under the front wheels of the vehicle.

The company which is building these horseless wagons has its manufactory on Long Island, on the shores of the East River.  It claims that its engines can do the work of one horse at a cost of 1 cent an hour.  In order to be prepared for steep gradients and rough pavements, the strength of these wagons is to be three horse power, so that the fuel cost of using all the power of the engine will be 3 cents an hour.

Like all the improvements made in steam engines, from the invention of Watt to the latest marine engine or locomotive, the changes in this gas or petroleum engine have been in matters of detail, rather than by the application of new principles.

Having once found a practical method of utilizing gas explosions produced at regular intervals, the inventive minds of the world set to work to strengthen the weaknesses of the primary type of explosive engine.  The irregularity of motion was corrected by the introduction of a flywheel heavy enough to take up and carry on all surplus force of the gas at the moment of its explosion.  The piston was thus brought back by the momentum acquired by the flywheel to the position in the cylinder, where a fresh explosion had the greatest propelling effect upon it.

Then it was found that when the work to be done was less than the normal power of the engine, too many explosions occurred, the machine ran too fast, and there was a great waste of fuel.  This defect was remedied by an ingenious application of the principle of the regulation governor, by which the gas valve was not opened when the speed of the engine exceeded a certain limit.  Again, the cylinder in which the explosion took place became so hot after a time that the entire engine was liable to be smashed, owing to the expansion of parts made to fit accurately.  A water jacket around the cylinder and a circulating cistern in connection with it prevented this catastrophe.  The heated water flowed out above while the cold water ascended, became heated, and passed into the cistern in its turn.

With such improvements, many of them trivial in themselves, but all of them important in making the machine commercially practicable, the ordinary gas engine came into general use and established itself where intermittent work of small horse power was required.  It was then in the condition of Watt's engine before Stephenson proved by the Rocket that a steam engine could be used for portable as well as stationary purposes.

To make gas engines as portable as steam engines was naturally the next step.  Here inventors were confronted with the difficulty of carrying the gas itself.  Many tanks were made of steel or copper, into which the gas was forced until high pressures were obtained, but the result was unsatisfactory.  No matter how much gas was condensed, its bulk was enormous when compared with a solid, such as coal, or a liquid, such as petroleum.

Numerous efforts were made to utilize the energy of coal directly—that is, without the intermediate form of steam.  When these failed, attention was turned to petroleum as a liquid fuel of great heating power, economical bulk, and with no appreciable residue after combustion.

A German inventor, about nine years ago, found that he could make use of the ordinary gas engine with some modifications as a consumer of liquid hydro-carbons, variously known as petroleum, naphtha, paraffine, or gasoline.  The chief change was the addition of a small heating chamber into which the liquid fuel passed before it entered the cylinder.  Beneath this chamber a petroleum burner was lighted, and its metal covering made so hot that the petroleum vaporized as soon as it entered the chamber.

The freshly prepared gas was then in position to explode in the cylinder as soon as it was mixed with air.  A small portion of each charge was allowed to escape through an opening near the top of the cylinder, so as to come in contact with the naked light which heated the vaporizing chamber.  These various steps were automatically regulated by valves which regulated the force and time of the explosions.

Thus the petroleum engine was formed by which fuel could be conveniently and economically carried in a reservoir placed close to it.  The next problem was to diminish its size.  This was accomplished by shortening the stroke of the piston rod, and at the same time enlarging the cross section of the cylinder.  This gave a shorter connecting rod between the piston crosshead and the pin on the flywheel.  In order to gain increased power with a shorter stroke, the speed of the engine had to be accelerated from 120 to 600 revolutions per minute.

Moreover, the questions of smell and noise obtruded themselves at this point, and these matters were all treated together.  Those who have noticed how a perfectly fitting glass chimney and a well-trimmed wick on an ordinary parlor lamp banish smoke and smell can appreciate the long course of experiment by which the odorless petroleum engine was finally obtained.  Perfect combustion was what was desired, because in that case the residual product of the combustion of petroleum were carbonic acid, gas, and water.  If the various openings were too small the disagreeable odors of imperfect combustion would be evident.  If they were too large, available energy would be dissipated without acting on the piston.  The noise was muffled by an ingenious arrangement of the exhaust.  The final result was a short, squat engine, eighteen inches high, for two horse power, with all its parts so compact that it might easily be hidden in the cupboard of an ordinary office desk.

At the speed and endurance contest between various kind of horseless carriages, held in France in July, 1893, thirteen petroleum motors and two steam motors started from Paris for Rouen, a distance of seventy-five miles.  The quickest passage was made in five hours and forty minutes by a four-passenger steam carriage, which weighed 4,400 pounds in running order.  Although this weight per wheel is not excessive, being not greater than that on each of the wheels on comfortably filled Fifth Avenue stages, it is not light enough for any roads except those paved with granite sets or laid down in the best macadam.  At fourteen miles an hour even macadamized roads would suffer considerably, and this was about the commercial speed attained by the steam carriage between Paris and Rouen, while the actual running speed must have exceeded this rate.  Its engines developed twenty horse power, and were capable of hauling 2,200 pounds at a speed of eighteen miles an hour on the level, or or ten miles an hour on an upward gradient of 10 per cent.

Its supply consisted of 110 gallons of water and 2 tons of coke.  It was thought by the experts that this steam carriage might be able to do valuable service in time of war, but they held that it failed in lightness, elegance, and convenience, and awarded it only the second place in the contest.

Four carriages, built by two makers, though carrying petroleum engines of the same design, jointly carried off the first prize.  Two of these were for four passengers, one for three, and the other for two.  The two-passenger carriage weighed, in running order, 1,700 pounds.  The motor was a two-cylinder petroleum one, fixed with its axis parallel to that of the carriage, having a velocity of 700 revolutions a minute.  It operated on the hind pair of wheels through a friction gearing, which permitted four rates of speed—three, five, seven, and ten and a half miles and hour.  The wheels of these carriages had rubber tires, and the brake was applied to a drum fixed upon one of the axels.  The petroleum or gasoline employed had a density of .7, and the mean consumption was ten cubic inches an hour for the two-passenger carriage.

It was thought strange at the time that no electric carriages were entered for this contest, but the great weight of the storage batteries and the difficulty of finding dynamos at convenient places to recharge them explained their absence.  Since then, however, an enterprising Frenchman has invented a four-passenger electric carriage which weighs altogether 2,573 pounds, including 330 pounds for two passengers, 240 pounds for the motors, and 925 pounds for the accumulators.  The batteries are of the Fulmen type, and the motor produces 2.6 horse power at a velocity of 1,200 revolutions per minute.  The carriage is capable of making a trip of eighteen miles without recharging at a maximum rate of twelve miles an hour on a good, level road.  Extra power is obtained for steep gradients by coupling the inductions in quantity instead of in tension, but the waste of power is considerably greater in this form of coupling.

With the increasing popularity of the bicycle and its effect in producing a better class of roads there is sure to be a trial of these automobile carriages in this country before long.  There has recently been a marked revival of the use of road traction engines in the western part of this State.  There is also a bicycle company in this State which promises to put a machine on the market worked by a petroleum motor, though it has not yet done so.

It must be remembered that Trevithick, who built the first locomotive, did not intend it for rails but for roads, and the hope of finding a motor commercially practicable without the use of rails has always been kept in view by great mechanical inventors.