Living languages are fluid. As new words are coined, others become obsolete. Definitions change with passing years. King George I of England, upon inspecting Sir Christopher Wren’s masterpiece, St. Paul’s Cathedral, told the famous architect that his creation was “amusing, awful and artificial.” Sir Christopher was delighted with the royal compliments. Three centuries ago amusing meant amazing, awful meant awe-inspiring, and artificial meant artistic. With time as dimension in universal communication, we would have to choose our words with care. The accelerated scientific progress of recent years will doubtless continue, with new ways and means of cosmic communication being developed. Radio astronomy itself is barely three decades old. Revolutionary techniques in interstellar contacts may be just around the corner. * * * * * Has radio communication with alien beings already occurred? This is a startling possibility. On August 22, 1924, the planet Mars approached to within thirty-four and a half million miles from the earth. Radio broadcasting stations were silenced and scientists listened for a possible message from across space. At the suggestion of the late Dr. David Todd, professor emeritus of astronomy at Amherst College, the U.S. Government through diplomatic channels requested that all countries with high-power transmitters silence their stations for five minutes every hour from 11:50 p.m. August 21 to 11:50 p.m. August 23. Station WOR, Newark, N.J., reported receiving a word translated as “Eunza.” Other stations announced receiving strange signals. Twenty-three years later, in 1947, Gene Darling, an early “ham” operator and General Electric Co. employee in Schenectady, N. Y., said he and an assistant had failed to turn off a test transmitter. “It kept on sending out automatic code signals,” he said, “and fearing criticism, we never told of our mistake.” But something else happened during this 1924 test period of silence that remains a mystery today. C. Francis Jenkins, of Washington, D. C., had only recently invented a radio photo message continuous-transmission machine. He was asked by Dr. Todd to take a record of any signals received during the periods of silence. The recording device was attached to a receiver adjusted to the 6,000 meter wave length. Incoming signals caused flashes of light, which were printed on the film by an instrument passing over its surface from side to side. The film was in a roll, 30 feet long and six inches wide, and it was slowly unwound by clockwork under the instrument and light bulb which responded to transmitted sounds. When the film was developed, it disclosed a fairly regular arrangement of dots and dashes along one side, but on the other side, at almost evenly spaced intervals, were curiously jumbled groups each taking the form of a man’s face.