was slowly but steadily forced through the rock reef. With this danger past, the remainder of the work was comparatively simple, and the tunnel was rapidly pushed on to the New York heading.

As the work advanced, the course of the tunnel was carefully plotted out, and the excavating shield was steered by increased pressure in one or another of the hydraulic jacks, in order that it should be brought into perfect register with the brick lining of the New York heading at the point of juncture. So careful were these calculations, that when the shield met this heading, the lateral alinement was found to be almost perfect; but vertically, an error of a few inches was made. This break is temporarily sealed with blocks of wood driven into the silt above the shield, as shown in one of our photographs.

While the shield was being operated by the English company, it was noticed that instead of remaining stationary on its axis, it was gradually turning clockwise as viewed from the front. Every effort was made to stop this movement; but it continued, until now, having traversed 3,400 feet of silt, it presents the appearance illustrated, with the vertical plates lying almost horizontal. This curious action was probably due to a slight deflection of the plates in front of the diaphragm of the shield, which tended to turn the shield through an imperceptible angle every time it was jacked forward, and these slight deflections gradually accumulated until they became quite noticeable. The tunnel has an internal diameter of 18 feet 1 1-2 inches, and is lined with cast-iron segments 1 1-2 inches thick, braced with webs and formed with inwardly-projecting flanges, which provide means for firmly bolting the sections together. At present a pressure of 22 pounds per square inch above normal is still maintained in the greater part of the tunnel, to prevent water from seeping through the joints of the lining, which have not yet been calked up. The shield must now be dismantled, and the castiron sheathing or lining run out to join the brick lining of the old heading. The shell of the shield, however, can not be removed, and will be buried behind the cast-iron lining, a final sacrifice to the work it has served so long and faithfully.

Some further work remains to be done on this tunnel before it will be finally completed. The English company, in order to save the cost of cartage, spread the silt, as it was excavated, over the

floor of the completed section, and as a consequence a large part of the tunnel on the Jersey side is more than half filled with this material, and it must all be removed before the work of laying car tracks can be commenced.

The south tunnel, which is being run parallel to the completed tunnel, is also being excavated from the New Jersey side, and is now well under way. A distance of three-quarters of a mile remains yet to be tunneled. A new shield was built for this work, and in anticipation of the difficulties encountered in the north tube, it was provided with an apron, which can be moved out in front of the shield to permit blasting out rock in front of the cutting edge.

We illustrate herewith a new shield, now in position, which will continue the north tunnel through the city under Morton street and Ninth avenue to Tenth street, where the New York station is to be built. The course of this tunnel, together with the proposed extension, is shown in the accompanying map. The purpose is to continue the tunnel up Tenth street to Sixth avenue, and thence up to Herald Square, with intermediate stations at Greenwich, Fourteenth, Eighteenth, Twenty-third, and Twenty-eighth

streets.

These tunnels are intended only for the use of electric cars, and not, according to the popular misapprehension, for heavy railway trains. It is the opinion of the engineers that the silt foundation is too soft to permit the passage of heavy weights through the tunnel. The silt, though very compact under the weight of the water above, nevertheless has the properties of a viscous fluid, and it is feared that it would yield under the impact and weight of a heavy steam or electric locomotive. Such yielding, though but little, would place a tremendous bending strain on the cast-iron lining, above what it could bear, and ever so slight a rupture would result in dire consequences.

A combined elevator and air lock is in use at the head of the New York shaft. The elevator shaft ends in an air lock at its upper end, and the circular platform of the cage, when in its highest position, completely closes the mouth of the shaft, and forms the bottom of the air lock. As the compressed air is released from the lock, this platform is forced snugly in place, making an air-tight closure. The cable by which the elevator is suspended must, of course, pass through

Foreign View of American Railways.

"The railways of America are commercial undertakings on a gigantic scale, and are operated under conditions which are to be found nowhere else in the world,

impressed by the courage with which the railroad officers have faced their difficulties and the pluck with which they have overcome them. It is impossible to associate with the great men who have made their mark on American railways, I may say American national history, without being infected with some of the enthusiasm they show for their business, and no man can travel over their railways

without becoming possessed of a great deal more knowledge than he previously had or without getting many valuable hints. American railway men are quick to see a new idea; they are quicker still to try it; they take a great pride in their profession and are all striving to get at the science of it. That their methods are not always perfect is what might have been expected; but they have managed to do what no other country in the world has done, and that is carry their goods traffic profitably at extraordinarily low rates, notwithstanding the fact that they pay more for their labor than any other country. It is in the study of how they do this that much benefit can be derived by other countries, and if I have in some degree succeeded in throwing light upon their methods, I shall feel that I have benefited others as well as myself by my visit to that great country, where the courtesy of the people is exceeded only by their hospitality."

The above is, in the main, the "conclusion" reached by Neville Priestley, under secretary to the government of India's railway department, in the report he has just made to the Indian government on the working of the transportation department of American railroads. Mr. Priestley was commissioned by the Indian government to make such a study, which he did last year, and his report on "The Organization and Workings of Railways in America" contains an unusually clear presentation of and insight into the railway transportation problem as it is presented in the United States.

Mr. Priestley makes clear the fact that the keynote of American railroad organization is the utmost possible freedom of initiative for the individual official, combined with strict responsibility for results. He quotes one high official as putting it this way: "Do what you please, but get the results and don't make too many mistakes. That is the policy. Hands off every one. Put the load on the man and change him if he is unsuitable." Mr. Priestley finds this to work well, and produce what he calls "the most satisfactory results." The system makes men willing to assume responsibility and encourages them to do their duty fearlessly. He says: "Extraordinary as it may seem, the confidence placed in the good faith of the men engaged in railroad operations is very great; and the mutual trust is still greater. It is recognized that the best results can only be obtained by allowing

every man to run on his own feet. Mistakes are expected, but even if precautions could prevent them, the taking of these precautions is considered to destroy individuality and to deprive the employer of the man's best efforts. Under the system pursued, each man does his very best unrestrained and is always striving to bring himself to notice either by suggestions tending to improvement or economy or by showing good results, or both. This, and the system of advancing men by merit, are responsible for the highly intelligent service to be found today in the railroad profession in America."-Railway World.

Compressed Air in Naval Warfare.

At the outset, at least, compressed air has figured prominently in the Russo-Japanese War. Three of Russia's most powerful warships in the Far East have been seriously damaged, if not permanently incapacitated, by Whitehead torpedoes, which derive their energy for propulsion from compressed air.

While the original torpedo was nothing more than a submarine shell fired from a gun the mouth of which was below or close to the water line, the improvements made in this instrument of naval warfare have resulted in a craft able to navigate and automatically direct its own movements independent of the power which first launches it on its course of intended destruction. The modern Whitehead torpedo, which is used by the Japanese and the American navies, is really a submarine craft equipped with an engine of its own. A small but very powerful three-cylinder engine, operated by compressed air, is used to drive the screw which propels it. The compressed air is contained in a reservoir which answers a double purpose, that of furnishing motive power and a buoyancy chamber which will keep the craft from going to the bottom as soon as it is launched.

Various other methods of supplying power have been tried, but none with success. Compressed air has these two important advantages which no other means of power transmission can offer. While compressed air has weight, it is relatively very light when compared with any other means of supplying power. And this lightness is an all-important feature for such a device. Then it can be stored for an indefinite time with the knowledge that it will be ready for action

Another Device for Automatic
Control of Trains.

The use of a glass rod or pipe in connection with the air-brake system of a train, in such a way that the rod will be broken by a projecting arm or lever in case the engineman should attempt to run past a signal set in the stop position, is an old idea advanced or experimented with quite a number of years ago. The breaking of the glass would effect the escape of the air and set the brakes. The Barberie system, which employs the glass pipe and is designed somewhat on these principles, was recently exhibited by models in New York City. At the side of the track, a desired distance in advance of the home signal, there is a dwarf semaphore, the movements of which correspond with those of the home signal. From the side of the locomotive there is a piece of glass pipe hanging downward, in such a position that it will strike the dwarf semaphore, when that signal is set in the stop position, and be broken. The immediate effect is to bring into play in the cab a steam mechanism which shuts the throttle, locks it, applies the air brakes and finally deposits sand on the track. Only after the train has stopped can the engineer unlock the throttle, and he must first adjust a fresh glass rod in place of the broken one. The apparatus is so designed that if the engineman, having his train under control, wishes to do so, he can prevent the smashing of the glass rod, and run slowly to the home signal. To keep the rod from hitting the dwarf semaphore, he manipulates a mechanism in the cab which shifts the position of the "destructible member" and saves it from injury. When he does so, a record of the time is made automatically on an indicator. The Railway and Engineering Review.

New York Air Brake Catechism.— This is the title of a new book by Robert H. Blackall, author of Westinghouse Air Brake Catechism. It gives a detailed description of all the parts of the New York air brake system, their operation, troubles, and the methods of locating and It includes and remedying the same. fully describes as well as illustrates the triple plain triple valve, quick-action valve, duplex pump, pump governor, brake valves, retaining valves, freight equipment, signal valve, signal reducing valve, and car discharge valve. It is a handy, practical catechism containing nearly 1,000 examination questions and their answers on the New York air brake and signalling apparatus, with special chapters on the care and maintenance of the air brake system, covering the subject of the New York air brake in every It contains special instructions detail. to firemen, engineers, trainmen, foremen and inspectors, has 250 pages, is fully illustrated and is bound in cloth. The price of the book is $1.25, and it is published by The Norman W. Henley Publishing Company, 132 Nassau Street, New York City.

Modern Air Brake Practice, Its Use and Abuse.-The author, Mr. Frank H. Dukesmith, in his introductory states that "realizing that the average air brake instruction book is written in a style much too hard for the ordinary reader to understand, has endeavored to illustrate the principle on which the air brake works by drawing comparisons with things commonly met with in the daily life of every one, and has avoided technicalities as much as possible.

To

still further simplify the study of the brake he has divided the subject matter into three distinct sections. By this system the reader will find that the knowledge necessary for the proper handling and care of the air brake can be acquired in the shortest possible time and in the very easiest manner when compared with any other plan."

Section I explains and illustrates the various parts of the air brake equipment and their duties. Section II treats of the various defects and their remedies. Section III treats of the philosophy of air brake handling, together with tables and rules for computing brake power, leverage, etc. The Westinghouse air brake system is fully treated, particular attention being given the subject of the