coal and ashes for sixty-five of the largest buildings in the down-town district; and there seems to be no reason the economy and cleanliness of its work being considered-why it should not eventually put practically all this work below the surface of the ground. In addition to ashes, there is an enormous amount of waste paper and other rubbish originating daily in the big down-town buildings, which at present helps to litter the streets and which the tunnel company will be able to handle advantageously and economically.

damage done to the street pavements by these heavily loaded wagons and drays.

By January 1, 1905, the Illinois Tunnel Company will have facilities for handling underground not less than 50,000 tons of freight per day. Already architects, in the designing of wholesale and manufacturing buildings within the loop, are beginning to provide for the construction of sub-basements forty feet below the surface, on a level with the tunnels, these sub-basements being intended for use as freight yards or shipping rooms for the firms occupying the buildings.

Another purpose served will be the hauling of freight to and from freight depots and business houses. Chicago is one of the greatest railroad centers in the world. No less than twenty-five trunk lines of railroad radiate from it. The aggregate annual volume of freight tonnage is enormous almost beyond computation, and it is all received and distributed from six freight depots, which are located within a territory only one and a half miles square. At present this freight is handled in trucks, the enormous number of which constantly block traffic, to say nothing of the daily

Details of Construction

The freight cars of the company are of steel and iron construction throughout, and each car measures twelve feet over all. They are of the double-truck, eightwheel type, and are built as combination cars, which can be used either as gondolas or flat cars. As a box car, one of these vehicles will measure 48 inches in width, and will stand 63 inches above the rail; while the box will be 10 feet 6 inches long. The weight capacity of each car is 30,000 lbs. The cars are so constructed that they can turn on a curve of fifteen-foot radius. It is said that they

will carry anything that can be passed through the door of any regular freight car now in use.

The tunnels themselves are of horseshoe shape, with walls, roofs, and bot

should be allowed to come closer than 24 feet 6 inches from the surface of the street. In this way, in the opinion of the city officials, sufficient space was left for the construction of a subway for the passage of street cars, if, in the future, such should become necessary.

Before beginning the actual excavation, a large amount of preliminary work was found necessary; and it was not until September, 1901, that the first gang of miners were started at a point in the alley between Madison and Monroe streets, immediately west of La Salle street. As rapidly as possible thereafter, seven other shafts were started, the basements of

ELECTRIC LOCOMOTIVE AND LOADED FREIGHT CAR.

toms of solid concrete. They are of two types-trunk conduits, II feet 21⁄2 inches wide and 12 feet 6 inches high, inside measurement; and lateral conduits, 6 feet wide and 7 feet 6 inches high, inside measurement. The smaller tunnels have 13-inch bottoms and 10-inch walls and tops; the trunk tunnels, 21-inch bottoms and 18-inch walls.

The freight locomotives are each operated by a single electric motor, and are of low and compact construction. The third-rail system of operation is used, the rail consisting of a steel strip half an inch thick by four inches wide, clamped between insulated wood stringers laid lengthwise in the center of the track. This rail, besides furnishing the current, is provided with openings for the teeth of cogwheels, which are mounted on the underside of the engine, the rack and pinion system being used, and the wheels carrying only the weight.

The tunnels offer a speedy and convenient method of transporting the mails to and from the central postoffice, its many branches, and the various railroad depots. At present mails are carried almost entirely by wagon on the street surface. The company hopes eventually to secure the contract for this transportation, though as yet no definite arrangements have been made.

In the building of the tunnels, it was decided, after consultation with the city engineer, that the roof of no tunnel

SHAFT No. 3, LOOKING NORTH.

buildings located at the points selected being leased for the purpose. The work of excavating was done by three shifts of men, working eight hours each. The first shift of miners went on at 4 o'clock in the afternoon, and worked until midnight; the second shift went on at midnight, and worked until 8 o'clock in the morning; the third shift, which was known as the "concreting" shift, went. on at 8 in the morning, and worked until

they had completed the job before them, it being arranged that they should get through so that the miners could begin promptly at 4 o'clock in the afternoon.

A total of about 850 men were employed in the tunnel construction, about 600 additional men being employed in the office force, in the hauling of cement, gravel, and other materials, and in the carrying away of the excavated dirt. For the purpose of expeditiously getting the excavated dirt to the elevator houses, where it was lifted to the street level, 900 little tram cars were used. These tram

TUNNEL AT STATE AND LAKE STREETS, LOOKING NORTH.

cars were only four feet long and twenty inches wide, and Chief Engineer Jackson believes that largely because of the smallness of these cars there was no delay in getting the immense quantity of dirt out of the way of the concrete gang who followed so closely behind the miners.

The little cars, loaded with dirt, were lifted by elevators to the mouths of the elevator shafts, where they were dumped into waiting wagons, and then promptly sent back down the shafts for fresh loads. So perfect were all the arrangements and so rapidly was the work done, that in ten and a half months of actual work, no less than twelve miles of tunnel was completed, and that without any accident to workmen, or, on the testimony of Chief Engineer Jackson, a single complaint from a pedestrian or property owner.

Relief of Street Congestion The down-town streets of Chicago are almost continually blocked by the wagons of teamsters who are carrying away the dirt excavated in constructing the basements and foundations of the great skyscrapers and other large buildings which are always in process of construction at various points inside the loop. This congestion the company hopes to relieve by contracting to remove through its tunnels the excavated dirt and other debris where old buildings are torn down. That this plan is more than a mere theory, is shown by the fact that the company has recently signed contracts to do this work in the case of two large buildings now in course of erection in the down-town district.

It also hopes to be able to relieve the congestion still further by conveying to the site of new buildings all or most of the material necessary in their construction. How great a relief it would be to have new buildings go up on their own ground, with no blocking of sidewalks and streets by loading and unloading wagons, every citizen of Chicago knows without the telling.

These are some of the principal ways in which the company expects to make its large investment profitable, at the same time leaving the surface of the streets free for the use and transportation of the 'people. If this is as yet chiefly an unrealized dream, unanimous Chicago will hope to wake up one day to find that the dream has been largely fulfilled.

Electric Power

Power for the operation of the tunnel railroad will be furnished by a generating plant capable of producing 5,000 horsepower, for the construction of which the company is now about to let the contract. Direct current at 250 volts will be used, the rails acting as a return. Power for experimental purposes has been furnished by the Chicago Edison Company. The trains will attain a speed of between fifteen and twenty miles an hour.

The original purpose of building the tunnels as conduits for the cables and wires of the Illinois Telephone & Telegraph Company has not been lost sight of. These wires-now serving more than 5,000 subscribers-are carried along the

side walls of the tunnels, and there is plenty of space left for many times that number, the ultimate aim of the company being to supply at least 100,000 separate automatic telephone stations.

The company's plans include the extension of its present twenty miles of tunnels to nearly sixty miles, the territory to be tapped reaching from 71st street on the South Side, to Kedzie avenue on the West Side, and to Fullerton avenue

on the North Side, the tunnels on the outskirts being reduced in size and adapted only to the carrying of telephone and other wires.

The chief interest, however, in the plans of the company, so far as the general public is concerned, lies in the present effort to relieve the congestion of the down-town streets by carrying freight and other commodities far down underneath the surface of the streets.

O one who looks through the current engineering journals, it is unnecessary to say that there is at present a great deal of interest being displayed in the subject of water treatment. The railroad papers of the United States may especially be noted as giving more space to this than to any other one topic. The awakening of interest in this country is many years behind the appreciation of the question in Europe, where it has developed to a point sufficient to establish certain principles. It would be well for some of the many who are rushing into the business of water treatment in this country, if they would investigate the conditions of the problem somewhat carefully before investing their time and money in schemes that are predestined to fail-or, perhaps I should say,

to fail again. In view of what has occurred in other fields, it is not surprising that all sorts of water-softening devices should now be thrust upon the market. The inventor-chronic and otherwise sees the demand, and hears of the success others have made. The field is invitingly easy; all you have to do is to get the hard water into something, stir something into it, and the deed is done. The first water softener with which the writer had to do was built upon that principle, and it cost the company with which he was connected a good many thousand dollars to install the tanks, etc., and a couple of hundred to clear the ground of them about a year and a half later. There is now in operation at this plant a water softener which occupies a ground space fourteen feet by eleven feet, and which