Wunder the city of Baltimore was con

HEN the great double track tunnel

structed to shorten the route of the Baltimore & Ohio Railroad between New York, Philadelphia and Washington, the railroad company was the first to employ the services of electric locomotives for the handling of trains in the city limits. The ponderous engines which are the most powerful in the world, are at present operated by means of the trolley system, getting their power from overhead wires.

The great cost of maintenance of this system and the consequent care in keeping it in repair, has induced the company to install the third rail system, and work is progressing rapidly toward its completion.

The electricity is furnished by an immense electrical plant which not only furnishes the power for the operation of the locomotives, but also the light for all of the Baltimore & Ohio properties in the city, as well as several private concerns.

In order to utilize all of the current and take up the surplus of electricity that is generated at the power house at moments when the locomotives or lights are not used, an enormous storage battery will be used.

Some idea of the size of the battery may be obtained from the dimensions of the building to hold it. The building will be 145 feet long by 44 feet 6 inches wides.

The battery will consist of 320 tanks made of hardwood lined with lead, each tank holding 39 plates, 19 negative and 20 positive. Each tank will weigh, with plates and electrolyte, about 1,800 pounds, and the complete battery will have a capacity of 1,200 horsepower for a short period of time.

The horsepower of the electric locomotive ranges from 1,000 to 1,500, and this entire load has to be supplied from time to

time by the powerhouse at Howard and Montgomery streets. As this load is only required when the locomotive is in service, it is a very spasmodic one, the average throughout the day being less than 500 horsepower.

When the battery is put in service it will act as a reservoir of power, accumulating electricity while the locomotive is not in action and relieving the station of the load above the average by discharging into the line this accumulated current. To effect this, the station is only connected to the line through a booster, which is the combination of a motor and a generator. The generator is put directly in the circuit and is so designed that it only allows a certain amount of electricity to pass from the station to the battery and line. the locomotive is not in service this current goes through the battery and charges it. When the locomotive is put in service the current is diverted to the line, and as by the nature of the apparatus no more can come from the power station, the battery must give out the extra current to operate. Thus the station will be operated at a greatly reduced and highly economical rate, and the extra power dispensed with may be put to other useful purposes.

When

When the battery is installed and the new third-rail system is placed in operation the railroad company will have, according to electrical experts, the most modern system of heavy electric haulage in the world.

Taken in connection with the fact that the Belt Line of the Baltimore & Ohio was the pioneer in the application of electric locomotives for handling regular train service, this improvement adds another interesting feature to a plant that has already attained world-wide prominence in the field of electricity.

W

HILE Washington is not a manufacturing city, with large industrial. enterprises requiring the use of monster weighing machines, or "scales," as they are commonly called, it has many weight-determining balances, and one at least which leads all others in this country. The large scales upon which entire freight cars, with their loads of many tons, are weighed are considered colossal, but with all their immensity they are meagre in the eyes of Uncle Sam, who went the railroad magnates of the country one better" by installing at the navy yard the largest pair of scales in the country.

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This machine can outweigh the largest railroad scales by fifty tons, and when it is considered that its results must be accurate to a pound, while railroad scales are considered good when they come within fifty pounds of the exact weight, the result obtained is little less than marvellous. The scales are scarcely two years old, having been brought here during October, 1898, and set in position in the south end of the big navy yard near one of the gun shops. A track leads from the gun shop to a forge and crosses the flooring of the big scales about ten feet east of the entrance to the latter building. A considerable period of time was required for the manufacture and erection of this monster machine. It was brought here in sections, and the greatest care was exercised in reassembling the various sections of steel so that the poise of the broad platform should be exact.

of the human body, is invisible to the eye. The most intricate parts are in a broad pit below the ground. Close investigation, however, and a foot rule would show that the platform of the machine is forty-eight feet long and twelve feet wide. Beneath the powerful machinery is a cement base, laid upon long piles. The ground is somewhat low, and it was necessary to utilize the services of a pile driver to secure a stable foundation. A solid base is one of the prime requisites of a perfect weighing machine.

When the Government sought bids for the erection of the machine, notices were sent to all the leading scale manufacturers in the country, and the lowest bidder received the contract. Much of its fine and peculiarly sensitive apparatus was specially manufactured for use in the big machine, which differs in its parts from any other scales in the country. The completed structure is regarded as the finest of its kind in the world, a model and marvel of modern mechanism, as well as a splendid achievement for American ingenuity.

Hundreds of visitors have trod across this platform without knowing they were near one of the most interesting mechanical contrivances in the national capital. They are not mentioned in the guide books, and the men at the navy yard do not call attention to the scales, par excellence, unless, perhaps, a flat car happens to be on the platform being weighed with its load of two or three great guns. All the large ordnance manufactured for the navy is weighed upon this machine. It was built for that special purpose and has given eminent satisfaction, two years of usage having failed to dull its sensitive nature; yet it has done its work each day in a dull, ponderous way, with no meed of praise except from a few naval officers.

There is nothing attractive about the scales. From the surface of the ground they look like ordinary hay scales. Their delicate mechanism, like the vital organs

In order to illustrate the accuracy of the counterpoise of the huge machine to a reporter an officer in the bureau of yards and docks picked up a half brick which was lying near by, and tossed it upon the platform of the big scales. He then consulted a long brass lever in the reading box along the edge of the platform and found that the weight of the brickbat was just one pound.

Turning to the reporter he said the machine is so sensitive that it will give the exact weight of anything from a pound of feathers to a pair of 13-inch guns, and do it accurately. The capacity of the scales is 150 tons, or double the capacity of the old set, removed when the present apparatus was installed. A 13-inch gun weighs about fifty-five tons. Two of these monster instruments of war, reclining on a 48-foot car truck, can be weighed on the machine without taxing its capacity.

The nearest approach to the navy yard scales to be found in this city are the big weighing machines of the railroads. Though the navy yard machine now compels them to take a back seat, they were once envied by the smaller scales as the giants of the capital. The Baltimore & Ohio Company has one of similar capacity in its yard within the city and there is another set of scales of like capacity at its grain elevator and new coal pier.

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