tors tested. The original report gives the curves of pressure on pump inlet both developed by the straight-bladed pump impeller cut down to 34-inch diameter for the English radiator and by the USD-9A radiator with curved-blade impeller used with the Loomis system.

Various precautions described in the original report were taken to insure the correctness and comparability of results obtained with various radiators.

One of the interesting features developed in the tests is that the greatest difference between air temperature and water outlet temperature was found at altitudes between 3000 and 5000 feet, which tends to prove the assertion that a radiator which is adequate up to 3000 feet under rapidclimb conditions will probably provide sufficient cooling capacity for all

purposes.

The following conclusions are made in the report, which also gives the main data secured in tabular form.

Taken on the whole, the USD-9A radiator tests yielded quite good figures for efficiency, which can be depended upon as reliable. The efficiency values obtained in the various trials of this system were:

With no engine top cowl, bottom cowl with extra louvers-91 per cent. With extra louvers in top and bottom engine cowls, average of two tests-88.8 per cent.

With standard top cowl and no louvers in bottom cowl, average of three tests-87.8 per cent.

These figures indicate that although something is gained by extra louvers in the cowling, still the engine and its front bearer in the USD-9A obstruct the flow of air through the nose radiator to such an extent that the only great gain to be obtained would be by using wide lateral openings in front of these two units to exhaust the air passing through the nose radiator.

Steaming falsifies the apparent efficiency of a radiator, as it reduces the amount of cooling required to be done by the cooling system. A steam calorimeter in the overflow tube would be necessary for accurate corrections.

The only comparisons possible with the other radiators tested must be based on the figures obtained during those trials where no steaming of the other units took place. The comparative results obtained in such tests, with corresponding figures for the USD-9A system, are given in Table 1.

The addition of engine top cowling must produce less effect on the new cooling system than on the other two radiators mentioned in Table 1, for the reason that part of the total cooling surface of the new system, represented by the booster radiator, is independent of all cowling above or below the engine, provided, of course, the lower cowling does not obstruct the auxiliary unit when in its lowest position. The addition of shutters on the nose radiator also produces less effect on the USD-9A cooling system than on the others, and for the same reason.

With this radiation system any reasonable increase in cooling capacity can be obtained by adding to the height of the auxiliary radiator. It is quite probable, however, that the present amount of auxiliary radiation is sufficient in view of the fact that very little steaming was encountered even under the severe conditions of the tests. Under ordinary conditions the high-compression Liberty engine is not intended to be run at full throttle near the ground, as was done in these tests.-Mechanical Engineering, 19/3.

AERONAUTICS

OCEAN FLIGHT WITHIN MONTH.-England, Says Admiral Taylor, May Try Dirigible Next Week.-Rear Admiral D. W. Taylor, Chief of the Naval Bureau of Construction and Repairs, announced that the navy would be ready to attempt the flight by heavier than air craft across the Atlantic Ocean within a month.

"I do not believe that Great Britain will beat us across," he said, “if the attempt is made with heavier-than-air craft.

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We are under the impression in Washington, however," he continued, "that a dirigible trip will be undertaken by England possibly during the coming week. The navy has four flying boats of the N. C.-1 type, and work on these is almost completed. It has not yet been decided whether all four will be sent over at the same time, but I believe that more than one will start. That will insure against total failure should one or two break down."

Admiral Taylor said that he was not certain whether a non-stop trip would be attempted. "We may break into two hops," he said, "and this will entail the use of airplane mother-ships, vessels equipped with oil, gasoline and food."

Through their wireless apparatus," he added, " mother-ships can keep in touch with the flying boats. Although the flying boat may alight only once at sea, it is possible that more than one mother-ship could be used."Baltimore Sun, 18/3.

The United States Navy Department has successfully carried out the experiment of launching an airplane from a dirigible balloon. The airplane was attached by a 100-foot cable to the dirigible; both rose to about 3000 feet and then the airplane was released; after diving about 1000 feet it obtained sufficient speed to continue its usual flight.-Mechanical Engineering, 19/3.

AIRSHIP WAS UP 100 HOURS.-A British airship, according to General Seeley, recently remained in the air for more than 100 hours. At an average speed of 50 miles an hour, the Under Secretary added, the airship must have covered more than 5000 miles. It was possible that the airship could have continued longer in the air, notwithstanding the fact that it encountered considerable wind.-N. Y. Times, 22/2.

MAKES AIR-FLIGHT RECORD.-Lieutenant Harmon Negotiates Washington-New York Route in 85 Minutes.-The Director of Military Aeronautics issues the following:

Lieutenant Frank H. Harmon, pilot of Bolling field, Anacostia, February 19, established a record flight from Washington to New York by airplane in a La Pere plane.

He landed at Hazelhurst, N. Y., 85 minutes after his "take off" at Bolling field.-U. S. Bulletin, 27/2.

GIANT SEA Planes Make NEW RECORD.-Two giant United States naval flying boats of the F-5-L type broke all records in a 300-mile non-stop flight from Hampton Roads to New York City yesterday. The flight was made against a strong head wind in four hours and a half. Each of the two great flying machines carried seven passengers and a gross load of 13,000 pounds.

During the flight the A-1070, one of the two flying boats, developed trouble in one of her 400-horsepower Liberty motors. While the huge machine continued on in the teeth of the stiff breeze Chief Mechanic Sacks overhauled the defective engine and succeeded in repairing the fault in mid-air. After this the flight proceeded without further incident.

The two big flying boats-the A-1070 and the A-4036-rose from the choppy waters of Hampton Roads exactly at 10 o'clock, March 12. They tied up to the buoys of the naval air station at Rockaway just as the naval guard struck five bells at 2.30 o'clock March 12.

The flight was made for special reconnaissance work as well as to establish a record. It also gave to the navy officials valuable data in connection with the plans for the coming attempt to cross the Atlantic in a flying boat two and one-half times the size of the F-5-L's.

Each of the two boats carried a great quantity of photographic apparatus, and valuable photographs and moving pictures were taken during the flight. These are to be shown at the Aeronautical Exposition to-day by the photographic section of the United States Navy.

The A-1070 was piloted by Ensign Souther. As passengers she carried Lieutenant W. L. Richardson, chief of naval aviation photography; Ensigns Marbury and Morrow, Chief Mechanicians Sacks and Driceland and Radio Operator Bowman.

The A-4036 was piloted by Ensign Irvine, and her passengers were Ensigns Pulliam and Sinclair, Photographer Kramer, Mechanicians Nice and Bark and Wireless Operator Miller.

Wireless telegraph and telephone communication was maintained between the two ships and with the shore stations throughout the flight. Two homing pigeons, used by the navy, were also carried.-Baltimore Evening Sun, 13/3.

BIGGER AIRPLANE FOR OVERSEAS FLIGHT NOW BEING RUSHED AT NAVY'S FACTORY.-A type of naval airplane, which in point of size, power, and carrying capacity exceeds the N. C.-1, is now under construction at the Navy's League Island aircraft factory in Philadelphia, it became known yesterday when an aircraft designer, who had been at the factory, described its features in detail.

The designer, who would not consent to have his name made public, said that work on the plane was going on night and day in order to have it ready as soon as possible for the contemplated transatlantic flight. Officials of the navy's air service, he said, had great faith in the new flying boat, and believed it would accomplish a trip to Europe with little or no difficulty.

The design of the new super-airplane, which is known as Model T, is similar to the navy's F-5, now being shown at the Aeronautical Exposition in Madison Square Garden and the 69th Regiment Armory. It has an upper wing span of 250 feet, which is 124 feet more than the N. C.-I. The lower wing is 25 feet less. The length of the craft over all is 80 feet. The wings are 12 feet broad and 14 feet apart.

The motive power for the new naval airplane will be supplied by five Liberty motors of 400 horsepower each. Three will be tractors and two pushers.

Seventy-five passengers will be able to ride comfortably in the Model T, according to The Times informant, making ample allowance for tanks carrying sufficient gasoline and oil for a flight of 2000 miles. The N. C.-1, has carried 51 passengers on one of its trips. If the new Model T lives up to the hopes of its builders, it will establish a new passenger-carrying record.

Construction on the machine has progressed so rapidly that its completion is expected in the very near future, according to the aircraft designer who told of its details. He was unable to express himself more definitely as to the date of its completion, he said, because of the many unforeseen difficulties which arise in building airplanes of a new type.N. Y. Times, 2/3.

HELIUM." When the armistice was signed one of the experimental plants which had been operated at Fort Worth, Texas, had successfully

produced helium at the rate of 3000 or 4000 cubic feet per day, but as this production was far below what would be required for the needs of the War Department and the Navy Department, to say nothing of that of our Allies, it was determined to undertake production on a large scale, and for this purpose contracts were entered into by the Navy Department, acting for both the War and Navy Departments, for the construction of a plant at Fort Worth having a capacity ten or twelve times as great as the experimental plant from which helium had been produced.

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The necessary machinery for equipping this plant is now nearing completion, and the buildings will soon be under construction.

"In order that the supply of this rare gas may be conserved contracts have been entered into with the owners of the wells supplying it, by which the use of this gas for domestic purposes will be limited to such an extent as to conserve it for a period varying from 10 to 20 years. The necessity of doing this will be evident from the fact that foreign governments have already shown the greatest interest in this gas and are making every effort to secure a supply of it. The importance of conserving it is so great, however, that officers of the War and Navy Departments believe that Congress should lose no time in enacting legislation which will secure to the government the sole control of all helium-bearing gas in this country. "In explanation of the great military value of the gas it is stated that one shot from an explosive bullet is sufficient to explode the hydrogenfilled balloon of any airship, while the same balloon filled with helium is absolutely safe from attack.

This was thoroughly demonstrated by the Navy Department before the signing of the armistice by conducting experiments at Anacostia on balloons filled with hydrogen and others filled with helium, which, at the time, was disguised under the name of argon. One shot into the hydrogen balloons was sufficient to explode them, while a number of shots into the argon-filled ones produced no effect other than a scorching of the envelope at the point of entrance of the bullet."-Secretary Daniels Nat'l Press Club Speech, 25/2.

THE DOUBTFUL FACTORS IN THE PROBLEM OF TRANSATLANTIC FLIGHT.— That a flight across the Atlantic Ocean will be made in the immediate future is almost certain. It is, in fact, altogether remarkable that isolated feats of this kind have not been achieved before now. The establishment of anything like a regular aerial transport service over the Atlantic is, however, quite another matter. It would be unsafe to predict how soon, and under what conditions, this will be realized.

The monumental report of the Civil Aerial Transport Committee, recently published in England, embodies some discordant ideas on this interesting question. Few persons give more study to the problem of transatlantic flight than Commander Porte, whose preparations to undertake such a journey in the summer of 1914 were terminated by the outbreak of the war. This authority, as quoted in the report just mentioned, believes that the direct route between Ireland and Newfoundland is at present out of the question, and that for many years to come the only practicable route will be by way of the Azores. Commander Porte also considers Newfoundland an unfavorable terminus for the westward journey, on account of the obstacle opposed to a safe landing by the notorious fogs of that region. He prefers a landing ground on Long Island, though its distance from San Miguel (Azores) is about 2250 nautical miles, as compared with 1346 miles from San Miguel to Newfoundland.

The elements of uncertainty in transatlantic flying are almost wholly meteorological. The proposed Azores route offers the advantage of the trade winds for the westward journey. Whether, and to what extent, the counter-trades, which blow above the trades and in the opposite direction, could be utilized for the return journey to Europe is still doubtful, because we lack precise information about these winds; particularly as to the level

at which they blow. In higher latitudes westerly winds prevail, but they are much interrupted by cyclonic storms. Here, again, the question arises whether it would be possible to fly high enough to secure comparative immunity from adverse currents.

That the coasts of Newfoundland are habitually shrouded in fog seems to be taken for granted in all speculations about Atlantic flight. The British report, however, contains two communications from authoritative sources which emphatically discredit this idea. Sir E. Morris, who has lived and yachted along the Newfoundland coast for years, declares that fog prevails there only with winds from a quarter between northeast and southwest, while the prevailing winds are from west and northwest. He has seen a whole season from April to November pass without rain or fog. He also emphasizes the fact, borne out by a letter from another resident of Newfoundland, that the fogs of that region are generally very shallow. This, we recall, was likewise the experience of the U. S. Coast Guard observers.

The moral of all this seems to be that a meteorological and aerological survey of the North Atlantic Ocean and the adjacent coasts should be undertaken as soon as possible, with special reference to the needs of aeronautics. That air lanes across the Atlantic are destined to become of great economic importance hardly admits of doubt. The study of surface meteorological conditions over the ocean, the corner-stone of which was laid by Maury in the middle of the last century, has yielded results of indispensable value to mariners. Maury depended for his data upon the mariners themselves; but the Maurys of the air should better this plan and anticipate the demands of aerial navigators, by a systematic campaign of scientific expeditions ad hoc. This method would obviate heavy losses in both life and money in the early stages of trans-ocean flight.-Scientific American, 3/1.

AERIAL MAIL IN THE UNITED STATES AND ABROAD.-By Otto Praeger, Second Assistant Postmaster General.-The Aerial Mail Service was inaugurated May 15, 1918, and during the first six months of its existence its operations covered 68,892 miles, at a cost of $75,165.94, including 6 per cent on investment and 333 per cent for depreciation. In that period it carried between Washington and New York 74521⁄2 pounds of aeroplane mail. The revenue derived was $60,653.28. The net deficit, not taking into account the 6 per cent interest on investment, was $8,969.08. In addition to the aeroplane mail carried there was dispatched between Washington, Philadelphia, and New York in the six months' period a total of 91,9261⁄2 pounds of first-class mail, aggregating 3,667,040 letters. This mail was advanced in dispatch from 6 to 12 hours, which many times made up for the small deficit in the operation of this service. This ordinary mail was letter mail from distant states, which was carried in addition to the aeroplane mail. Thus the ordinary mail put on the planes at Washington was usually mail from the South Atlantic Coast states and the Gulf states, distributed to carriers by the Railway Mail Service before reaching Washington, and by reason of aeroplane dispatch was delivered in New York on the same afternoon instead of the following morning.

The Washington-New York route was established not as a typical commercial line, but to solve the problems that had to be met to establish a daily dependable schedule. The flying record made on the New YorkWashington line has never been equaled in the history of aviation, and its operation by civilian flyers of the Post Office Department has far exceeded its operation while under military control, the civilian fliers having a record of but seven forced landings in 100 consecutive flights and only two failures in that time on account of fog or storm conditions. The mail has been carried in blinding rain and hail, on fog-bound days with visibility of not over half a mile, and in the face of gales. Only two winter gales were strong enough to prevent the aeroplanes from com