National Geographic : 1949 Apr
Lord Rayleigh (1842-1919); Sir William Ramsay (1852-1916) G AS-FILLED electric-light bulbs, used by the millions today to furnish efficient illumination, trace their origin in a sense to the discovery of the gas called "argon" by John William Strutt, third Lord Rayleigh. Equally important, the finding of argon led to Sir William Ramsay's work in identifying other new gases in the earth's atmosphere, including helium and neon, which now have important commercial uses. Argon is a colorless, odorless gas compris ing 94-hundredths of one percent of the air. It is used commercially, mixed with nitrogen, in electric-light bulbs. Such lamps, filled with gas under pressure, give more light than the vacuum type, because the filament can be kept hotter without breaking down. The discovery of argon resulted from a painstaking effort by Rayleigh and Ramsay to learn why nitrogen released from ammonia by a chemical process had a slightly smaller atomic weight than nitrogen obtained from the air. A trace of an inert gas mixed with the latter accounted for the difference, they found, and it was named "argon." Born November 12, 1842, Rayleigh was an aristocratic landlord scientist like Robert Boyle, and succeeded to his father's title as baron in 1873. He was educated at Trinity College, Cambridge, where he distinguished himself in the 1865 Mathematical Tripos. Rayleigh received the Nobel prize in physics in 1904, was elected President of the Royal Society a year later, and in 1908 became Chancellor of Cambridge University. One of Rayleigh's most famous works, his Treatise on the Theory of Sound, still a lead ing textbook on the subject, was begun during a cruise on the Nile. The trip was taken on a dahabeah, a sailing houseboat, following a severe attack of rheumatic fever which the scientist suffered soon after his marriage to Evelyn Balfour, sister of A. J. Balfour, later Prime Minister. Rayleigh succeeded James Clerk Maxwell (page 510) as head of the world-famous Cav endish Laboratory of Physics at Cambridge in 1879. There he undertook research on the "redetermination of the electrical units (the ampere, volt, and ohm) in absolute meas ure," which resulted in a classical series of papers published by the Royal Society. Most of Rayleigh's researches, however, were carried on in a stable loft laboratory on his estate, Terling (pronounced Tarling) Place, near Witham, in Essex, to which he retired after five years at the Cavendish Labo ratory. There, in a somewhat crude and homemade workroom which no doubt would seem pitifully inadequate to the research workers of today, he continued his monu mental contributions to physics for 35 years. World-wide honors and distinctions came to him. He was one of the original members of the Order of Merit, instituted at the time of the coronation of King Edward VII. His genius was widely recognized in the United States. He was elected a member of the American Philosophical Society in 1886, and foreign honorary member, American Academy of Arts and Sciences, in 1888. In 1895 he and Sir William Ramsay received a Hodgkins Fund award of $10,000 from the Smithsonian Institution, the Barnard Medal from the Na tional Academy of Sciences, and the Cresson Gold Medal in 1914 from the Franklin In stitute. In 1884, at 42, Rayleigh presided over the Montreal meeting of the British Association for the Advancement of Science. Sir William Ramsay (page 527) was so closely associated with the work of Lord Ray leigh that one can hardly be mentioned with out the other. Born in Glasgow, Ramsay was primarily a chemist, and won the Nobel prize in this field in 1904, the same year that Ray leigh won it in physics. Both men were deeply interested in abnor mal psychology and members of the Society for Psychical Research, of which Rayleigh was a president. Their work on argon led Ramsay and Prof. M. W. Travers to the finding of helium, neon, krypton, and xenon. These are chemically inert elements which exist in the earth's at mosphere, some in very small quantities. Neon is the essential ingredient of the familiar "neon signs." The gas gives off a bright red glow when an electric current is passed through it. Helium had been found in the sun in 1868, but Ramsay first discovered it on the earth. He found that it was given off by certain minerals when heated. Today, obtained in large quantities from natural gas, helium is widely used in dirigibles, since it is noninflam mable and nonexplosive. These qualities led to the choice of helium for inflation of the National Geographic So ciety-U. S. Army Air Corps stratosphere bal loon Explorer II, which set a still unbroken altitude record for human flight, 72,395 feet, on November 11, 1935. About 250,000 cubic feet of helium were used, expanding to 3,700,000 cubic feet at maximum altitude. Use of helium enabled Captains A. W. Stevens and 0. A. Anderson to carry out the flight in safety, collecting data of great value to aeronautical science.