eliminated every possible wrong way, experiment number nine thousand and one revealed the right way to build the ideal storage battery.

After it had withstood every kind of shop test successfully the improved battery was given a trial on a Lansden wagon under actual service conditions by one of New York's big department stores. The larger size battery known as "Type A-6," weighing 1,200 pounds was put on a wagon weighing 2,460 pounds, making the weight of wagon and battery 3,660 pounds. On its first trip, in May, 1909, this wagon was run three consecutive days without recharging, covering in that time a distance of ninety-three miles over hilly roads in New Jersey and Staten Island.

miles an hour for the actual running time. On another test the "Greyhound" covered ninety miles in a day, making about a hundred stops. The charging plug was taken out at eight o'clock in the morning and was not put in again until 3:30 o'clock the next morning.

For three weeks the "Greyhound" was given the meanest service the chief engineer and garage superintendent could think up. It averaged fifty-seven miles a day for the period and regularly returned good for ten or eleven miles more. Then they had to admit that the "Greyhound" was capable of serving the longest and hardest delivery route operated in New York City and that no driver, even with a boy to assist in delivering the goods, could drive the wagon as far

This satisfied Edison, so the storage battery factory was re-opened and the men recalled. Then, while the factory was busy building batteries for wagons and carriages, which went off like the proverbial hot cakes, he sent for R. H. Beach, electrical engineer and expert on street cars.

"Do you know anything about street cars?" asked Edison.

"Do I? Why, I could build a street car with one hand tied."

"My dear Mr. Beach, the whole trouble with the trolley car," said the inventor, or words to that effect, "is that it is built by men who know all there is to know about it. The result is the same as it has been in the history of all great undertakings since Pharaoh, or whoever it was, built the pyramids: either they do not progress, or they progress backwards.

"The street railway is in the same predicament as the steam railroad: more power is wasted in hauling superfluous dead load than is needed for transporting paying live load. If this craze for building ponderous steel cars is carried much farther we may expect to see the time when the heaviest locomotives the rails will support will only be able to haul trains on the level, and passengers will have to get out and walk up hill as they did in the good old days of the stage coach. The new storage battery, if enough cells are put in, will run the regulation trolley car; but what's the use?

It would be done at a criminal waste of money, though the battery would not be to blame for that but only the needless dead weight of the car, and though the waste would be no greater than with the present methods of generating and using power.

"What we want to do is to get the proportion of dead load to live load down to an irreducible minimum. If we can do that the new battery will get all the glory and it will be in a position to stand on its own merits before anybody stops to figure out that we haven't wrought a miracle, after all, but have merely exercised a little horse sense.

"So I should like to have you approach this car problem with a vacant

without any undue reverence for standard practice. Never mind about how cars are built now. Begin at the first verse of the first chapter of Genesis and find out how a car should be built."

With this understanding, space was set aside for an experimental track, expert workmen were detailed to work under Mr. Beach's orders and early in 1908 the quest for the ideal street car was begun. Wheels being the foundation of a car, so to speak, experimenting began with them. An ordinary street car wheel is of cast iron, weighs about six hundred pounds, and costs about three cents a pound. Beach and his corps of Missourians broke them in testing machines until they knew all about the weaknesses of cast iron wheels. Then they made wheels of other materials and tested them until they found something that could not be improved upon. The ideal wheel was of manganese steel; and while it only weighed one hundred and twenty-five pounds, or less than a fourth of the weight of a cast iron wheel, it was actually stronger. And while a manganese steel wheel cost $23.75 as compared with $18 for a cast iron wheel the steel wheels were the cheaper investment, for the expense of rolling the weight of the superfluous nineteen hundred pounds of cast iron in four wheels around the street under a car would quickly compensate for the extra first cost of the better wheels.

Having settled the wheel question the next thing to do was to get axles to put them on. Any street car builder who knows his business will tell you that you cannot possibly get along with anything less than a four-inch axle for a fourwheeled car. By the same laborious process of experimenting that led to the discovery of the light wheel, an axle only two and a half inches in diameter was produced that afforded the same factor of safety as the clumsy four-inch.

As the roof did not have to support a trolley pole but was only needed as a protection from the weather, the thing to do was to find the lightest possible material that would have the requisite stiffness and strength. A wearisome lot of failures was scored before a molded roof that met all the requirements with

out adding an unnecessary pound to the weight of the car was produced. When it came to windows Beach went to New York to make the purchase in person.

"What have you that is suitable for car windows?" he asked of the dealer.

"American plate glass; that is what they all use. Of course it isn't really plate glass, but it's nice and thick and heavy.'

"Won't do at all. Have you nothing better?"

"M-m-well, of course, if you are willing to pay a little more I could give you French picture glass. It is clearer, much higher grade and is just as strong as the American plate glass but is only half as thick and heavy."

"Now you're talking. The greatest strength with the least weight is what I am looking for."

Every detail was worked out in the same painstaking way until the first car was completed. It did not carry an unnecessary pound of material anywhere. In fact, it wasn't strong enough. That much was foreseen; the point was to find out exactly how much was lacking. That car was taken out on the experimental track behind the high board fence where Beach and his corps harried and abused it as if it had been a wild bull and they

Spanish bull fighters until it went to pieces. Another car, lighter, stronger and more practical was built and again Beach and his matadors tortured the poor thing into wrack and ruin.

Profiting by what failures had revealed, a third car was built and turned loose on that experimental track. Except that it was lighter and more graceful it looked just like an ordinary trolley car seating twenty-six passengers. It was operated by the same mechanism, managed by the same controller, but the car itself weighed but seven thousand pounds and the storage battery three thousand pounds more, making a total weight of ten thousand pounds as compared with an average weight for a trolley car of the same capacity of twenty thousand pounds.

Beach's matadors did their worst to Car No. 3. They chased it up and down. and around the track at slow speed, high speed and half speed, with full load and no load at all. They tried everything their ingenuity could suggest; but when the experimenters had reached the end of their resources and Edison's bank account was smaller by seventy-five thousand dollars that last car wasn't feazed.

Then Beach went to the telephone and called up an old friend, a street railway

manager who had been vastly amused by the idea of any one trying seriously to improve upon the twentieth century trolley car. Upon being invited to attend the first appearance of the new storage battery car upon any public track the street railway manager chortled out a derisive acceptance and added:

"And I'll bring the wrecking car with me to pick up the pieces for you."

Some one to whom a primrose on the river's brim is just a yellow posey and nothing more must have overheard that conversation over the wire for the news was spread broadcast that Edison's new storage battery car was to appear in the streets of Orange on a certain day accompanied by a wrecking car to pick up the pieces. When the time came for the gate in the high board fence to open the audience included besides the invited guests thirty-one reporters by actual count and all the small boys-and there are a good many of them-in Orange, East Orange, South Orange, West

Orange, North Orange, Middle Orange, and all the rest of the Oranges.

Storage battery cars not being provided with steering gear a team was hitched to one end for guiding purposes, the current was turned on and the car under its own power went bumping over the pavement to the street railway tracks. The instant it was on the rails the guests, invited and otherwise, climbed aboard until the car was packed worse than a New York subway train in the rush hour. At first Mr. Beach was inclined to be peevish over this unsolicited acceptance of his hospitality, but thought better of it when he reflected that if the new car stood up under such a test it would have nothing to fear from any possible condition of service.

That car was trundled around the tracks of the Oranges, including some of the stiffest grades in that locality for a distance of thirty miles. By that time everybody, including Edison who had managed to squeeze himself aboard, was

satisfied. Even the street railway manager who had come to scoff remained to sing the praises of the storage battery

car.

Next day orders were given to build an addition to the storage battery factory that would double its capacity. At the same time another large factory was set aside for car building, for the light construction system has been patented. The new cars are to be built on the automobile plan; that is, the various parts are to be manufactured in outside establishments that specialize in certain lines and the finished parts are to be assembled at the Edison plant in West Orange.

The storage battery car is capable of running one hundred and fifty miles without recharging at a cost of one cent a mile, and of climbing any ordinary grade. It saves twenty-five per cent on the cost of line construction, for there are no overhead wires, no poles, no transmission cables and no track bonding. There is also a material saving in the cost of power plant, too; for on a trolley line the power plant must be large enough to move the maximum amount of traffic, which continues for only a short time; the rest of the day there is a large surplus of power that is not used. The power station for charging storage batteries can be run at its most economic gait every hour in the twenty-four.

The greatest saving is in the cost of operation. The Edison patent storage battery car weighs only from one-half to two-thirds as much as the ordinary trolley car of the same capacity, yet the Edison car is the stronger. As it costs one hundred dollars per ton per year to run the average street car on the average street railroad it may be seen that this saving is of some consequence. Thus, if a trolley car weighing ten tons is required to haui a certain number of passengers a given distance and a storage battery car weighing seven tons can render the same service there would be a saving of $300 a car a year on dead weight alone, and on a hundred cars $30,000.

There is a loss of 25 per cent in power from the time the current leaves the generator in the power house until it

has been used in the motor of the car. But this is no greater than the average line loss in a trolley system.

The new car will be particularly adapted for service where traffic is light, since it brings the cost of construction and maintenance down to a minimum. It is equally well adapted for heavy traffic where overhead wires are not permitted and also where underground trolleys for any reason are impracticable. West Street, in New York, is precisely such a line. Street traffic being exceedingly heavy, overhead wires are out of the question. Underground trolleys are equally impracticable owing to the danger of flooding the conduits at high tide.

So the horse car has things its own way in West Street. Think of horse cars in the heart of the metropolis of the Western hemisphere in the year of grace, 1910!

The battery which has made the new type of street car possible is made up of cells built in two sizes. The larger size, suitable for cars, consists of a nickel plated corrugated steel retaining can 334 inches thick, five inches wide and 13% inches high containing the electrodes and the electrolyte, as the fluid in which the electrodes are immersed is called. The larger cell complete weighs 19.2 pounds, the smaller 13.5 pounds. The positive electrode consists of six plates each of which is made up of thirty tubes four inches long and about the diameter of a lead pencil. The tube is made of perforated steel filled with oxide of nickel mixed with flakes of pure nickel to increase the conductivity of the mass. The negative electrodes are plates consisting of gridirons each of which contains twenty-four flat rectangular pockets made of perforated steel and filled with iron oxide. Positive and negative plates are assembled alternately in the cell on rods connected with their respective poles, properly spaced by nickel washers and held in place by nuts. The outside plates are insulated from the can by sheets of hard rubber. The electrolyte is a twenty-one per cent solution of potassium hydrate with a small amount of lithium hydrate in distilled water. Each cell has a cover welded on containing four openings for the poles, for filling and for the escape of gas while charging.