AMONG the subjects of national importance which should command the attention of every enlightened citizen of the United States is that of the trade of South America and our own particular relation thereto. We commend for careful perusal the bulletin of the Pan-American Union for October, which deals with the trade of Latin America for the year 1910. The growth of the commerce of the twenty republics dealt with since 1897 is shown by the fact that whereas in that year the total commerce was 910,422,500, in 1910 it had increased to $2,343,744,000, a gain of over 150 per cent, which is about equally divided between imports and exports. These figures reveal the important and unsuspected fact that in the matter of commercial expansion Latin America has forged ahead more rapidly than the United States, the growth in foreign trade during the period referred to being $1,433,000,000 for the Latin American republics, and $1,581,000,000 for the United States. During 1910, 55.2 per cent of the imports into the republics of North America came from the United States and to the South American republics we sent 13.64 per cent of their total imports. Taking the whole group of the Latin American republics, both in North and South America, we find that the United Kingdom leads with 26.03 per cent of the total imports, followed by the United States with 23.31 per cent. The third place is held by Germany, with 15.4 per cent, followed by France, with 8.21 per cent. The United States lead in the matter of exports received from Latin America, with 34.51 per cent, the United Kingdom, with 20.99 per cent, being second, Germany, with 11.47 per cent, third, followed by France, which takes 8.29 per cent of the exports. Seventy-five per cent of the shipments from the republics in NorthAmerica come to this country, but we receive only 20.3 per cent of the shipments from the southern republics. We are free to confess that the results shown in this bulletin are more favorable, as regards the position of the United States in the Latin American trade, than we had supposed them to be. At the same time, in view of the great geographical advantage enjoyed by this country, as compared with our commercial rivals in Europe, our trade with the southern republics is far below what it should be. A better system of banking, one more adapted to conditions in South America; the exercise of greater care in selecting the representatives of our commercial houses who go down and get into personal touch with the Latin American business men; a more intelligent study of the character, disposition, tastes, manner of doing business, and particular ways and wants of the people down there—all this, coupled with the creation of a merchant marine specially constructed for the South American trade, would do wonders in the extension of our Latin American commerce. Personality and manners count for a very great deal with the Spanish American. There is probably no section of the earth where “bluff,” “push,” and general “get-there” methods count for so little, except as destructive agencies. The German, always analytical and scientific in his methods, thoroughly understands this fact; and the great commercial houses in Germany select their representatives with a special eye for their fitness for meeting and adjusting themselves to the idiosyncrasies of the Latin American customer. Instead of trying to make the people buy what he makes, the German tries to make what the people buy—a very simple, but a very radical and far-reaching distinction. More than that, he is careful to pack the goods and deliver them in just that very way which will render them acceptable to the customer and fit in most comfortably with his established habits and the general local conditions. The Quebec Bridge Competition A MOST important contribution to the literature of bridge engineering is an article by Gustav Lindenthal, in our contemporary, Engineering News, on the Quebec bridge competition, which not only throws a flood of light upon the inside history of this great undertaking, but also affords a mass of instructive technical information for those who are interested in the construction of long-span bridges. The Quebec bridge owes its celebrity mainly to the fact that it contains a longer single span than any bridge as yet constructed, its nearest competitors being the Brooklyn suspension bridge, with a main span of 1,595 feet, the Williamsburg suspension bridge, which measures 1,600 feet between towers, and the Forth bridge in Scotland, a cantilever structure, with two main spans, each measuring 1,710 feet in the clear. The cantilever structure which is to be built near Quebec will be 1,800 feet in the clear between centers of main piers. In 1889 the Quebec Bridge Company invited tenders for a structure to carry a two-track railroad with a wagon road and trolley line on each side. Out of six competitors, the Phoenix Bridge Company was awarded the contract for the construction of a cantilever bridge prepared by its own staff of engineers, the award being made on the ground, among others, that this company's plan was the lowest in price. The construction was commenced, and when one-half of the bridge had been erected, the structure collapsed under its own weight, with the loss of eighty lives and four million dollars in property destroyed. “The primary cause of both disasters,” says Mr. Lindenthal in the article referred to, “was the same: bad engineering; but in connection with the Quebec bridge was a contributory circumstance, of which it is difficult for engineers to speak without a feeling of humiliation, and that is the beggarly compensation for engineering services on a work of unprecedented magnitude, and the willingness of an engineer of high reputation and unimpeachable integrity to assume very important and laborious duties for a fee for which they could not possibly and seriously be met." In this connection we wish to emphasize the fact that in all great engineering works of this character, the very last direction in which economy should be practiced is in that of the employment of the highest type of professional men, both for the design and oversight of the work. When such men are engaged, the remuneration should be on a scale which will justify them in allotting that measure of their own time and of the time of their office and field force, to the work, which the importance of the job demands. We need go no further back than the recent failure of the Austin dam for another object lesson in the folly of practicing over-zealous economy in the matter of professional engi- ' neering services. The bridge fell because one of the main compression members in the bottom chord of the shore or anchor span, which had been designed to stand a pressure per square inch of about 30,000 pounds before beginning to give way, failed suddenly and without warning under about one-half that load, or to be exact, under 16,800 pounds per square inch pressure. Mr. Lindenthal scouts the theory advanced in some quarters that the blame is to be ascribed to lack of scientific knowledge of compression members, which it was alleged could be derived only from full-size tests of large columns. He rather lays it to the fact that no studies of any kind were made for the unprecedentedly large compression members of the Quebec bridge until after their failure. Says he, “The leading consideration for the choice of their cross-sections seems to have been the desire of the contractor for cheap manufacture, which was not balked by the engineer. The chord members consisted each of four slabs or ribs composed of a number of thin, stitch-riveted plates, with contact surfaces painted or rather greased, insufficiently stiffened with flange angles and flimsy lattice angles. They were of a form so obviously defective that they should have been condemned at first sight. They were a pernicious example of commercial engineering, which may be defined for this case as the subordination of design to the cheapest methods of manufacture, under the pretense of fulfilling specifications." The fall of the bridge was investigated by a Royal Commission of three Canadian engineers, who made an exhaustive and able report. Unfortunately the Canadian Government dispensed with the aid of that commission, whose report formed the basis of favorable comment at the time in the columns of the SCIENTIFIC AMERICAN, and appointed a new board, which, after much labor and time brought forth an official design, which, according to Mr. Lindenthal, cost the Canadian Government about five hundred thousand dollars and two and a half years' time of the Board. Bids were invited on this design, and bridge companies were invited to submit designs of their own; but they were expected to prepare these in four months' time and without any compensation whatsoever. Ultimately, out of the many and costly competitions, which included about twenty-four tenders and eight or nine competitive plans, and tenders varying from eleven million to sixteen million dollars, an independent design, drawn up by a Canadian company “in contravention of the official specifications,” providing for limited traffic capacity and costing only nine million dollars, was accepted by the Canadian Government. Had the design for this bridge been thrown open for world-wide and unrestricted competition by the leading bridge engineers of the world, the Canadian Government would undoubtedly have secured a better bridge, and certainly would have saved an enormous sum of money. In the latter half of his article, Mr. Lindenthal, himself probably the leading authority on long-span bridges, will show that the Canadian government ultimately will have spent nearly eighteen million dollars by the time the St. Lawrence River bridge is completed, and this in spite of the fact that by a wise and judicious policy it could have secured a bridge of greater capacity with a large margin of strength, for a sum of less than ten million dollars. Attempts to Produce Experimental Pellagra SO far the study of the horrible disease known as “Pellagra” has produced nothing to point to the etiology of the disturbances it sets up. The Italian expert, Dr. Sambon, believes that it is an infectious disease, and that it is transmitted by the “buffalo gnat” (Simulium reptans) ; Dr. Lavin-der, the specialist of the United States Public Health and Marine Hospital Service, thinks that the disease is a metabolic or food disease. But until the past year no one had tried to test the various theories by means of inoculations in one of the higher animals. If Sambon's theory is correct, an infection should be possible by means of the blood of a patient, since the organism that causes the disease must at some stage or other be present in the blood. To test this supposition, Dr. John F. Anderson, director of Hygienic Laboratory, and Past Assistant Surgeon Joseph Goldberger obtained some rhesus monkeys (Maccacus rhesus) and inoculated them with defib-rinated blood and spinal fluid from typical cases of Pellagra. Two of the monkeys showed slight dis-colorations of the skin on the face; these varied in intensity and disappeared after a short time, and they were different in the two monkeys. There was no fever or any other indication of disturbance after nine months. Dr. C. H. Lavinder, although he does not believe the disease to be due to infection, also attempted to induce the disease in a number of rhesus monkeys. In three monkeys he made intraperitoneal injections of blood from a patient, in three injections of spinal fluid, and in three injections of spinal emulsions. The emulsion was also used to inoculate culture tubes, with negative results. After six months, none of the monkeys showed any symptoms. Drs. Anderson and Goldberg suggest that the negative results may be explained in one of three ways: 1. The monkeys may not be susceptible to the disease. 2. The technic may have been defective. 3. The infective substance or agent may not have been in the blood or in the spinal fluid at the time it was drawn. These explanations all assume that the disease is infectious. But even on that assumption there is still another explanation possible. If the disease is caused by an animal parasite and is transmitted by the Simulium, there is the possibility that the organism undergoes developmental changes in the secondary host, without which it is incapable of producing the disease again. Science Preserving Hail-stones.—The peculiar formation of hail-stones and the probable conditions .if cheii production have long been matters of much merest to scientists. A thorough study of them, it is oelieved, might throw much light on various meteorological phenomena, especially in regard to air-currents, changes of temperature and of pressure, etc., in the upper strata of the atmosphere. A comparison of them with the “ice flowers” and snow crystals or stars which Tyndall and other prominent scientists have found so fruitful a field of investigation might yield important results. Heretofore, however, the comparative rarity of their occurrence and the great rapidity with which they melt, has offered obstacles to this. But Prof. Boris Weinberg, of Tomsk, Siberia, has just perfected an apparatus, as we learn from Les Annates, which is expected to obviate these difficulties. He will gather the hail-stones as opportunity offers and preferve them by plunging them in a liquid of about the same density contained in a double-walled receptacle like a superior ice cream freezer, but “packed'' with a mixture of ice and sulphate of topper. As needed for study the stones can be removed, sliced in extremely thin sections and photographed by a polarizing microscope or autochro-matic plates, as is done with anatomical preparations. The Eruption of Taal Volcano, in the Philippine Islands, which took place January 30th, 1911, and caused a loss of 1,300 lives, has been the subject of a large number of important papers in the scientific journals, besides the official reports of the Philippine Bureau of Science. One of the most graphic descriptions is that of Rev. M. Saderra Maso, which is published as a special bulletin of the Philippine Weather Bureau. This account is noteworthy for the attention devoted to the meteorological and seismological features of the eruption, and in this respect it is an important contribution to the science of vulcanology. This volcano has been the seat of repeated disastrous eruptions, the greatest of which was that of 1754. All the eruptions of which a record has been preserved have had the same character as the recent one, consisting of violent explosions which hurled the volcanic products to great distances. The huge vapor column of the last explosion rose to a height of from 20,000 to 30,000 feet, and was seen 250 miles away, where it was mistaken for a distant thunderstorm. One remarkable feature of the volcano is that no lava has ever issued from it in a liquid state, the ejecta being blown to dust and ashes by the pressure of gases or steam. The late eruption appears to have been marked by unusually magnificent displays of volcanic lightning. For three days preceding the eruption a constant succession of seismic shocks were felt over a wide area, and they caused much alarm in Manila, until the Weather Bureau located the epicenter in the region of the Taal Volcano. The partial vacuum produced at the moment of the explosion and the resulting diminution of atmospheric pressure set up strong winds blowing in toward the volcano. This wind was felt as far away as Manila (39 miles). At points nearer the volcano it assumed almost hurricane violence, impeding the movements of people who were trying to flee against it, producing tremendous waves on Lake Bombon, causing sheets of iron roofing to fly about, etc. At a distance of 14 miles Father Maso saw the cogon grass lying like wheat which had been beaten down by a storm. He is of the opinion that the wind assumed a rotary motion, in accordance with the general laws of storms, so as to produce a transient tornado or whirlwind. The atmospheric waves propagated outward from the volcano were recorded on biographs to a distance of 200 miles. Engineering Need for Navy Colliers.—The Navy Department has chartered six Scotch steamers and one American steamer to carry, coal from Norfolk to San Francisco for the use of the Pacific fleet. The Scotch steamers will charge $5.40 a ton; the “J. M. Luckenbach,” the only American vessel that competed, asked $8 a ton, which bid the navy accepted. Test of a 21-inch Torpedo.—A torpedo designed for the navy, during a recent teat in Sag Harbor by the Bliss-Leavitt Company, traversed more than ten thousand yards, when fired at a 32->knot speed. At 27 knots it covered a range of over 8,000 yards. Most of the torpedoes now carried by battleships and armored cruisers have a speed of 35 knots and a range of 5,000 yards. Dynamite for Farming.—Experiments were recently made in New Jersey to demonstrate the efficacy of a low-freezing explosive in aerating the subsoil and digging a hole for tree^planting. The discharge breaks u<p the adjacent ground and renders tenacious subsoil porous and sponge-like, thereby favoring a conservation of the moisture. It is claimed that a deeper root penetration becomes possible, and that the crops are not so sensitive to spells of dry, hot weather. The Twenty-second Dreadnought. —The “Centurion,” launched November 18th at Devonport, is the twenty-second dreadnought to be put afloat for the British navy. She will have a displacement of 23,500 tons, and a speed of 21 knots. The armament will consist of ten 13.5-inch guns and twenty-four 4-inch guns. Her armor on waterline and turrets will be 12 inches thick. She will 'have three torpedo tubes for the discharge of the new 21-inch torpedo whose effective range is 7,000 yards. The 1000-foot Vessel. —A dispatch from London says that the White Star Line has ordered from Har-land&Wolff a liner which will exceed the “Olympic” by one.hundred feet in length. As this ship measures 882% feet, it will be seen that the new vessel will be approximately one thousand feet long. Although the report lacks verification, it may well be true, although the question may be asked on this side of the Atlantic: “Where will she dock?” E'ven the Wlhite Star docks with their temporary lengthening of one hundred feet would not accommodate such a ship, whose stern would project over 80 feet into the North River. Praise for American Shipyards.—United States shipbuilders recently were paid a flattering tribute by Admiral Garcia, of the Argentine navy. The Admiral recently made a close study of European shipyards in connection with the letting of the contracts for the two battleships which are being built respectively at the Fore River yard and at those of the New York Shipbuilding Company. He stated tha.t in many points of equipment and management, our shipyards are decidedly superior to the most renowned shipyards of Europe—a statement which will not be surprising to those who are familiar with conditions in the best of our home yards. Expert Testimony on “Olympic” Collision.—The recent summoning by the British Government of Naval Constructor P. W. Taylor, U.S.N, as an expert witness in the Admiralty trial in connection with the collision between the “Olympic” and the cruiser “Hawke,” brings to mind tests made by Mr. Taylor in the model tank at Washington. These experiments with four models towed at different speeds and in various positions with regard to one another, show that one vessel overtaking another is repulsed by the forward vessel until an overlap- of one-third has been established. Then there is a sudden change, the rear vessel being strongly drawn toward the leading vessel. Aeronautics Fowler's Flight Eastward Across the Continent.— After being stuck in the sand 15 miles west of El Paso, Texas, for eight days with his Wright biplane, on account of a balky engine, Aviator Fowler finally flew over the town and landed within it on November 13th. He expects to finish his trip via New Orleans and the Southern States. Fight Aircraft with Mortars.—Recently the experiment was made at Sandy Hook of firing at aircraft with a 12-inch mortar, which proved that this was an effective weapon for the purpose. The mortar fired a shell filled with shrapnel, and the targets were a number of small captive balloons. The test proved very successful, even with balloons at high altitudes. Then a number of balloons were liberated, but even with free balloons the average of the hits was good. Experiments of this sort are soon to be conducted with aeroplanes as targets. Bomb-dropping from Aeroplanes in Actual Warfare. —According to the latest report from Tripoli an Italian military aviator succeeded in dropping four bombs into the Turkish encampment on November 1ft. The bombs, which contained picric acid, exploded, and a few hours later an aerial reconnoiter showed the Turks had vacated the spot. Flying over the- desert is quite similar to flying over the sea, according to the experience of the Italian aviators; but while at a height of 1,000 feet a fine view is obtained, if the aviator ascends 300 feet farther even, the earth is generally concealed by a blanket of fog. It is therefore difficult to reconnoiter at a safe elevation. The aviator who dropped the bombs also found it difficult to determine what damage had been done. It is therefore suggested that a second aeroplane should follow with an observer who can keep the pilot of the first aeroplane informed as to the havoc he is creating. An American Wins French Military Aeroplane Tests.— As forecasted- in the article on the French military tests, Charles T. Weymann, with his Nieuport monoplane, won the 186-mile cross-country race. He covered this distance in 2% hours as against 3^4 hours required by Prevost on a Deperdussin monoplane, which also was propelled by a 100-horse-power Gnome motor. Weymann's Nieuport weighed 483 kilogrammes (1,065 pounds) and carried as much again in live load and ballast. Thus over a ton was driven through the air at a speed of 72% miles an hour for a distance as great as from New York to Philadelphia and back. The fact that Weymann carrying so much weight averaged nearly as much as he did with a stripped machine in the International Cup race on July 1st last, is another proof of the small head resistance of the marvelous Nieuport monoplane. Orville Wright's Flights in a Glider at Kitty Hawk.— Upon his return home from his memorable flights without a imotor at Kiitty Hawk, N. C.—flights in which he remained aloft 7^4 and 9% minutes, respectively—Orville Wright said that these motorless flights were the most difficult he had ever undertaken, the conditions under wihich they were made being much more severe than those ever met with in a power-driven aeroplane. Measured with a Richard anemometer, the wind one day at the top of the hill had a velocity of from 17 to 25 meters per second (38 to 56 miles per hour), while 12 feet above the top of the hill the wind velocity was still greater. There was a difference of 5 meters per second in simultaneous observations made at heights of 6 and 12 feet, respectively. Mr. Wright believes his experience at Kitty Hawk will be of gireat assistance in designing new machines to meet severe weather conditions.