Here again subsequent workers have been unable to repeat the results, working under apparently the same conditions, and various plausible suggestions have been put forward as to why the original positive results were obtained. Garrett, in particular, has repeated with great care the experiments of Miethe and Nagaoka under a variety of conditions, without being able to de tect any formation of gold, although the presence of grammes of gold would have made itself evident to his tests. He reaches the conclusion that the gold in Miethe's experiments was derived from material in the electrodes and in the vessels. Garrett has further tried to convert tin into indium, and titanium into scandium, by Smits' method, without success. As regards Nagaoka's experiments, the theory has been attacked by Runge, and the experimental work by R. W. Wood, while the isotope of mercury invoked by Nagaoka in support of his theory has since been shown by Aston not to exist. The work of Miethe and Stammreich was extensively criticized at the conference of physicists (Physikertag) held at Danzig in 1925 (see Physikalische case of artificial transmutation, in quantities however small, by methods other than the a-ray method of Rutherford, has won ac ceptance. In the case of the reputed transformations of hydrogen into helium the source of contamination has been traced beyond a doubt , in the other cases where transmutation has been claimed there are no convincing theoretical grounds for supposing the process possible, there are many possible sources of error, and expert experimenters who have repeated the experiments have failed to obtain positive results.
For radioactive transformations, see bibliography to RADIOACTIVITY; for transmutations produced by a-particles, see bibliography to NUCLEUS.
For recent attempts at transmutations consult, under the names cited in the text of the article, the index of Nature, vols. 116, 117, 118, 119 (1925-27).
Full references to previous work are given by W. M. Garrett in "Experiments upon the Reported Transmutation of Mercury into Gold," Proceedings Royal Society, A, us, 391 (1926), and in "Ex periments to test the Possibility of Transmutation by Electronic Bombardment," Proceedings Royal Society, A, 114, 289 (1927). See also F. Paneth and K. Peters, "Heliumuntersuchungen," Zeitschrift fur physikalische Chemie, 534, 353 (1928), and same journal, Ab teilung B, I, I7o (1928). (E. N. DA C. A.) AND FLIGHTS. At Kitty Hawk, North Carolina, on December 17, 1903, Orville Wright (q.v.) made the first aeroplane flight in his tory. It lasted only for the brief period of 12 seconds, but later the same day Wilbur Wright (q.v.) flew for 59 seconds. Improve
ments and constant practice enabled the brothers in 1905 to make 45 flights, the longest of which was for 38 minutes. At Le Mans, France, on Sept. 21, 1908, Wilbur exceeded all previous records, flying 1 hour and 31 minutes over 56 miles, and the same year several flights by Henry Farman and Louis Bleriot exceeded 3o miles. The first notable flight over water was the crossing of the English Channel by Bleriot on July 25, 5909. At the open ing of the World War flights of two or three hundred miles were being made frequently.
The War intensified aeronautical activity and provided much spectacular achievement, but distance flying was not of course the primary aim. The post-war period beginning in 1919, however, witnessed the crossing of the Atlantic Ocean by both aeroplane and dirigible. The first successful flight across the Atlantic was made by men belonging to the U.S. Navy flying boat NC-4, piloted by Commander A. C. Read. Two weeks later the two Eng lish airmen Capt. John Alcock and Lieut. Arthur Brown made the first non-stop flight across the Atlantic, flying 1,890 miles from St. Johns, Newfoundland, to Clifden, Galway, Ireland, in 16 hours 12 minutes. Within a month the British dirigible R-34 travelled from Edinburgh to New York in four days, returning in 75 hours despite adverse weather conditions. Several other dirigibles also have successfully negotiated the Atlantic one or more times, notably the German Graf Zeppelin which after spectacular pio neering across the North and South Atlantic and around the world, inaugurated commercial service between Germany and South America.
The flight of Ross Smith from London to Australia inaugurated a number of distance flights by British fliers which were to prove the eventual feasibility of air-lines to distant parts of the empire, the speed record for this ro,000 mile course being brought in 1934 to less than three days by C. W. A. Scott and T. Campbell Black.
Meanwhile, American and French pilots contributed to the shortening of time over national and international distances. In 1923 the United States was first spanned from the Atlantic Ocean to the Pacific in a single flight ; in 1926, Admiral Richard E. Byrd flew to the North Pole from Spitzbergen and back, and the diri gible Norge crossed the Pole. In 1929 Byrd flew from Little America to the South Pole and back to Little America.
Lindbergh's perfect flight in 1927 from New York to Path attracted world-wide attention and stimulated flying achievement in all countries. By 193o, Dieudonne Coste and Maurice Bellont( had made the first non-stop flight from Paris to New York, an by 1934 Wiley Post had flown twice around the world, the seconc time requiring 7 days, 18 hours, 5o minutes for the flight o: 15,596 miles. In the same year, Maurice Rossi and Paul Cod(); stretched the non-stop distance record to 5,657 miles in a flight from New York to Rayak, Syria. By 1936, the American trans. continental record for the 2,500 miles from Los Angeles to Nev York had shrunk to approximately nine hours.
Thus, in the quarter-century following the World War al oceans and all continents were conquered by aeronauts of vari ous nations. (See also AERONAUTICS, AEROPLANE, AIRSHIP, etc.) (H. P. K.)