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engine, 3 per cent. It is desired to raise the back pressure 6 pounds above its present point. What must be the cutoff to maintain the same power of the engine without raising the boiler pressure?

The ratio for 1/5 cut-off and 3 per cent clearance, according to the table, is .54; and the mean pressure is (100+15) X.54 =62 pounds. If the back pressure is raised 6 pounds, the mean pressure must be increased the same amount in order to maintain the same power of the engine. This gives 62+6=68 pounds as the required mean pressure under the new conditions. As the boiler pressure is to remain the same, the ratio between the K

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mean pressure and initial pressure will become 68-115=.59. Looking at the table, under 3 per cent clearance, we find that the nearest ratio (which is .60) corresponds to a cut-off of 14.

Engines are usually designed to work most economically at a given cut-off, so that in most cases it is undesirable to change the cut-off to any extent. Raising the boiler pressure, on the other hand, is not so objectionable if the increase amounts to only a few pounds.

By means of one of the so-called "vacuum" systems, the exhaust can be used for heating purposes, without raising the back pressure at all, and in certain cases the pressure may even be reduced somewhat below atmospheric pres

sure.

Vacuum systems are of two general classes. In one, the radiators have two connections; but the usual hand valve on the return is replaced by a special automatic valve, which opens when in contact with water or air and closes as soon as steam strikes it. The returns are gathered into a single main, and are connected with a vacuum pump, which delivers the condensation and air into a re

ceiving tank, where separation takes place and from which the water of condensation may be pumped back into the boiler. Short circuiting through the various coils and radiators is prevented by the action of the automatic return valve, which causes each radiator to act independently of the others. This system is especially adapted to large plants and where several buildings are connected by long runs of horizontal pipe.

In the second class of vacuum systems the air valves are connected by piping with an exhauster or ejector, which removes the air from the radiators, thus allowing the steam to flow in to take its place. The condensed steam in this case flows to the receiving tank by gravity, as in the common pressure system. An ordinary expansion air valve may be used on the radiators, although a special form designed with reference to a free-discharge opening is commonly used.

The advisability of using a vacuum system depends entirely upon the conditions to be met. Where an old heating system, with small supply and return piping, is to be connected with a power plant to utilize the exhaust steam, it is frequently desirable to install a vacuum system, as in such cases it ordinarily requires from 5 to 10 pounds pressure to force the steam through the entire system of pipes and radiators. In old buildings where the grading of the returns is faulty, the vacuum system employing a pump to draw the condensation back to the receiving tank is especially desirable.

One point to be borne in mind in the design of any steam plant, is its simplicity; and, when mechanical appliances such as pumps, traps, automatic valves, etc., can be dispensed with without interfering with the proper working of a plant, this should be done.

With properly proportioned and wellgraded pipes, the pressure required for circulating the steam through a heating system, even of large size, should not exceed 2 pounds; and the work is often done at one pound or less. Now, the back pressure on an engine exhausting into the atmosphere is usually about two pounds, so that practically no additional load is put upon the engine when the exhaust is used in a well-designed heating system; the system simply acts as a large

condenser in which condensation takes place under a slight pressure instead of in a vacuum.

We found, in the first example given, that the increase in boiler pressure required to raise the back pressure from 2 pounds to 5 pounds was only 5 pounds, an amount so small that it could involve no harmful or wasteful results. So far as the efficiency of the radiators is concerned, it makes no difference whether the air is drawn out or forced out, provided that the radiators are steam-filled; and, as the temperature increases with the steam pressure, the heating capacity of a radiator filled with steam under pressure is slightly greater than when steam below atmospheric pressure is used.

Under the pressure system, air valves that are poorly constructed or not welladjusted, may prevent the radiators from freeing themselves of air. Vacuum systems, on the other hand, employ these de

vices. It is as necessary in one case as in the other that the valves be properly adjusted and cared for.

The vacuum system has a large field of its own, and is of much value in cases calling for the special features that it possesses. In modern plants with pipes of ample size, however, it would seem preferable to rely upon steam pressure for removing air from the radiators, and to rely upon gravity for returning the condensation to the receiving tank, rather than to install special mechanical means for accomplishing the same results.

In

any case, before the steam is allowed to enter the radiators it should be freed from oil, as far as possible, by being passed through some form of grease extractor; and, before discharging the water of condensation into the receiving tank to be pumped back into the boiler, it is also well to return this water through a settling chamber in order to remove any trace of oil that may remain.

The Year's Prosperity

SCIENCE AND INDUSTRY

So many things have arisen during the last twelve months to take up the attention of the average individual —such as the Panama Canal, reciprocity with Cuba, strikes, and other national topics that very few men have stopped topics-that to think of the unusual business prosperity that has marked the industries of the country during the past twelve months. As a rule, we have failed to note the fact, because our newspapers have been filled with reports of bank failures, Wall Street panics, and the constant mutterings of labor troubles.

During the early part of last year, the Secretary of the Treasury and the leading financial men in the East feared that when the great interior section of the country withdrew money from the New York banks to move the crops, the result would play havoc with the money market. Strange as it may seem, the crops have been moved without the slightest disturbance of existing conditions. It is also encouraging to note that the Treasury re

ports are of a character that indicates a genuine prosperity.

The last few months, with several bank failures, and a number of industrial establishments, railroads, and other corporations cutting down their working forces, the pessimist put in some good work. He prophesied that we had started on the down grade, that hard times would be upon us before we knew, but the truth is that our trade exports and imports were more favorable for 1903 than for the previous year.

The excess of exports over imports for the ten months ended October 31st, was $308,964,053. This was an increase in the balance of trade of over $11,000,000. Our export trade for the ten months showed the extraordinary increase of $62,202,021. A nation that sells more goods abroad month by month, need have little fear of an immediate industrial crash.

Our imports of foreign merchandise for the ten months up to the 31st of October showed an increase of over $51,000,000. This is another indication of

prosperity, for when times are hard and money scarce, imports from foreign countries are the first to be reduced. The actual available cash balance in the Treasury on the 31st of October amounted to the enormous sum of $223,144,309.

A grand boulevard is soon to be built through the crowded quarter of the old Another Oppor- city of Madrid; and this tunity for Ameri-modern improvement, can Enterprise which is started by the Spanish government, offers a fine opportunity for profitable investment to American capitalists. There are several reasons why the state has undertaken this enterprise, among them being the terribly crowded condition of the old quarter of the town, and the wish on the part of the officials to build up suburbs. The authorities also recognize the importance of improving the sanitary conditions of the city.

The plans of Architect J. L. Sallaberry have already been accepted by the government, and the Gran Via will soon be built. The following is the manner in which the government has subsidized the enterprise:

I. It grants eight years to the contractors in which to complete the work, and provides no penalty if the work is not finished within the specified time.

2. It sells to the contractors all the properties, inclusive of buildings, along the line of the projected boulevard, at the present rate of depreciated values, for which the properties have already been condemned.

3. It exempts forever from increased taxation the properties so acquired, after the boulevard shall be built.

4. It exempts forever the properties so acquired, from the 4 per cent sale and resale tax, which must be paid on all real estate sold.

5. It grants the contractors exclusively a perpetual franchise for a street-car and electric-plant system on the boulevard, which system is to be a mile in length, the franchise to continue at the pleasure of the contractors.

6. It permits the erection of ninestory buildings on both sides of the boulevard, and exempts the owners from taxation on modern improvements.

7. It permits the construction of

kiosks along the route, without taxation; and the placing of benches and chairs, for which the contractors may charge a certain price. A similar charge is now exacted along the existing boulevard.

8. It subsidizes the undertaking with 11,000,000 pesetas ($2,123,000), payable, with interest, in four installments.

Marine

While the United States is showing a satisfactory increase in many important branches of industry, and Our Merchant is invading with a large measure of success the markets of the Old World, we seem to be overlooking the fact that as a power-not referring to our engines of war, but to our merchant marine-the United States is far behind the other nations of the world, and is showing a decrease in tonnage each year.

An excellent editorial in Marine Engineering states:

"In 1810, when the population of the United States was about seven millions, 91.5 per cent of our foreign trade was carried in American ships of a gross tonnage of 981,000 tons. Forty-nine years later, at the outbreak of the Civil War, the proportion of our foreign commerce carried in American bottoms had decreased to 65.2 per cent, but the tonnage had increased to 2,496,000 tons. Now let us consider the discouraging statement of shipping for the past year. The tonnage in our foreign carrying trade has dwindled to 873,000 tons; we carried but 8.8 per cent of our foreign commerce; and moreover, not a single keel for a deepsea ship has been laid in this country for two years. It is difficult to realize the truth of these facts at a time when other industries are prospering and we are looked upon as the leading producing and manufacturing country of the world. Transportation by sea has, of course, necessarily kept pace with industrial expansion, and the British have been quick to realize the opportunity; their foreign tonnage has now assumed the enormous figure of 14,800,000 tons. Germany comes next with 2,960,000 tons. France and Norway have each about one-half of Germany's tonnage, and Italy's amounts to 1,180,000. The United States is paying annually foreign steamship corpora

tions one hundred millions of dollars for carrying our freight and passengers.

"These facts and figures are more than surprising. They will come as a revelation to the average American. They call for immediate investigation, and a remedy that will save our merchant navy and increase our shipyards."

Some time ago, an interesting article appeared in the Edinburgh Review unAmericanizing der the caption of "Amer

Scotland's icanizing Edinburgh InIndustries dustries." We quote the following to show how American methods are winning their way abroad:

"The 'one-break' system is another American idea which has gained a footing in this country and is rapidly growing in favor. By this arrangement the breakfast hour is done away with, and the men start work at 7 or 8 o'clock in the morning, having had a good meal, there being only one break during the rest of the day, for dinner. It is contended that this is a much better method, for both men and masters. The men do not start hungry; and being therefore fresher and better rested, they are able to pay more attention, and consequently turn out more and better work. Then, again, the waste, inconvenience, and delay caused by stopping, restarting at breakfast time, the annoyance of men coming in late, and the other evils of the twobreak system, are done away with; the output is increased; and the men are healthier and physically more fit to undertake the duties of the day. The onebreak system was first introduced into Great Britain by a Leeds firm in April, 1901, and was quickly imitated by another firm in the same town. The workmen at first raised an objection, on the ground that the day was too long to work with only one break, and asked either for a reduction of hours or a withdrawal of the system. The matter was subsequently discussed at a central conference of the Engineering Employers' Federation, where it was stated that 83 firms throughout the country, of which 26 were federated firms, had adopted the system, and were on an average working a 51-hour week. The experience of these firms, it was stated, was that the work

them, preferred the altered hours. In 13 firms the hours were divided as follows: Monday, 8 A. M. to 6 P. M., with the dinner hour from 12 to 1 o'clock; Tuesday, Wednesday, Thursday, and Friday, 7 A. M. to 6 P. M., with the dinner hour at the same time; Saturday, 7 A. M. till noon-a total of fifty-four hours. Of course, these new methods of premiums and the one-break system are applicable to any profession, and, indeed, the latter is in use in many other professions in Edinburgh."

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Since the Northern Railway of France discontinued the Paris to Arres Express, the Bristol and Paddington is now the fastest for its distance (1174 miles) in the world. There is, however, nothing in England to match the Twentieth Century Limited of the Lake Shore, or the Empire State Express of the New York

THE LATEST WORK AT ZOSSEN

CA

ABLE dispatches just to hand announce the closing for the season of the memorable series of tests made on the Zossen Road near Berlin with high-speed locomotives, at which velocities of over 130 miles an hour have been reached.

During the 22 months that have elapsed since the close of the first experiments, the track from Marienfeldt to Zossen has been taken up and relaid with new rails weighing 41 kg. (86.1 pounds) per linear meter, resting on heavy spruce ties 22 in. from center to center and heavily ballasted with broken basalt. The rails are set on each tie in a steel chair, strongly bolted down, and are joined perpendicularly by beveled joints, 7 in. in length, held firmly together by bolts passing horizontally through the fishplates, so that the effectiveness of a continuous rail is practically secured. The old light rails, which had failed in 1901 and were, therefore, taken up, have been laid down flat as guard rails, resting horizontally on special cast-iron chairs in such a way that the flat, bottom flange of the rail stands vertically along the inside line of each heavy rail and about 2 in. distant from the inner edge of its face. The track is a nearly level air line throughout its length, except one curve of 2,000 yards radius near its southern extremity, and is in all respects up to the highest standard of modern railway construction. The motors have likewise been improved in various minor details, but the cars are substantially the same as when first constructed. The car is shown in the accompanying figure. Each is 22 meters (72.18 ft.) in length and weighs 90.5 metric tons, or about 200,000 pounds avoirdupois. Of this weight 48 metric tons comprise the body and running gear, and 42.5 tons are made up by the motors, transformers, and other details of the electrical equipment. Each end of the car rests on a six-wheel bogie truck of the American type; and the motors are four in number, one attached to the front and rear axle of each truck, the midd pair of wheels in each group run

ning free. The wheels are 49 in. in diameter and are equipped with Westinghouse pneumatic brakes of the standard type. The transformers, which are hung beneath the middle section of the car, weigh 12 tons, besides which a storage. battery of 631 pounds weight supplies the current for lighting purposes. The interior of the car is provided with upholstered seats lengthwise along the sides, and an sides, and an open railing encloses at each end the space occupied by the driver.

* * *

As to results and observations during the trip, Dr. Walter Reichel, of the railway department of the Siemens-Schuckert Company, says: "After all arrangements have been made and the military posts along the line notified, the current is allowed to enter the car at 14,000 volts. We leave Marienfeldt 25 minutes after 9; and in starting up the current in each of the four motors, the power is gradually raised to about 2,600 hp. The feeding point is passed at 80 km. an hour. By the time Mahlow is reached (7 km. from Marienfeldt), a speed of 180 to 185 km. has been attained, and yet the train runs over the switches at this point without any particular shock. At this speed it is noticed that the current-collecting devices are still running quietly, and there is, therefore, no scruple as to further increasing the speed. The last resistances are gradually cut out under the load of 2,300 kw., and the speed rises to the hitherto unreached figures, 190 and 195.

While traveling at 195 km. an hour we noticed two people standing in the middle of the track about 800 meters ahead, apparently most calmly discussing high-speed traction with each other. Luckily, they heard the warning whistle of the signal pipe and got out of the way just in time. It would not have been possible to have stopped the 93-ton car within 800 meters, as it requires fully 11⁄2 km. to come to a full stop, at a braking pressure of 200,000 kg. * * * After the trip the car was examined very carefully and showed very little evidence of the demands which had been made upon it. The front of the car is covered with

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