One writer offered further proof (derived from an unnamed source) for the reality of the new bridge. Astronomers at Mount Palomar Observatory, he asserted, had made a secret study that confirmed the presence of the structure; furthermore a spectrographic analysis was supposed to have proved that the bridge was made of metal[XI-16]. Sensible comment on these statements is not easy. A “secret” study would be impossible since the moon’s face is obviously open to all viewers, and the purported chemical analysis is sheer nonsense. The spectroscope can tell the physicist what luminous gases are present in the atmosphere around a heavenly body, but it cannot reveal the composition of a solid object on the surface of the body, unless the object is first heated until it vaporizes and is transformed into gas. Before a physicist could make a spectrographic analysis of the alleged lunar structure, he would have to land on the moon and chip off a piece of the “bridge” itself. “_Pieces of Saucers_” In UFO publications, any oddly shaped chunk of rock or metal is likely to be described as a fragment of an interplanetary craft. A six-inch meteorite that fell at Sylacauga, Alabama, (_Chapter_ V) has been classified in one saucer book as an “unidentified crashed object.”[XI-16] By peculiar reverse logic, sometimes the absence of a solid fragment is adduced as equally valid evidence of flying saucers. The green fireballs of New Mexico (_Chapter_ V) were identified as spacecraft partly because they did not leave material traces on the ground. Similarly, when a small object apparently struck and went through a metal signboard in New Haven, Connecticut, on August 19, 1953, the object itself could not be found. Nevertheless, from a study of the size and shape of the hole and the material around the hole, saucer investigators, with more than Sherlockian skill, concluded that the object must have been a missile from outer space. To identify “pieces of saucers,” a new pseudoscience has now developed which we may call “xenochemistry,” the interpretation of substances allegedly from other planets. In xenochemistry, a full qualitative and quantitative analysis is usually not performed and exact results are not made public. From an identification and sometimes a quantitative estimate of one or two of the elements present in the specimen, the investigator infers the nature of the rest and treats the inference as proved fact. On the basis of this “analysis” he concludes that the object, before it entered our atmosphere, must have had a certain chemical composition that is unknown or impossible on earth and that the object therefore came from another planet. _Silver Rain in Brazil_