LINCOLN LAPAZ AND JEAN LAPAZ SPACE NOMADS METEORITES IN SKY, FIELD, & LABORATORY HOLIDAY HOUSE, NEW YORK COPYRIGHT, 1961, BY LINCOLN LaPAZ & JEAN LaPAZ PRINTED IN THE U.S.A. [Illustration: COURTESY OF AMERICAN MUSEUM OF NATURAL HISTORY Fireball speeding across field of camera during the photographing of the Great Spiral Nebula in Andromeda, by Josef Klepesta, at the Prague Observatory, Czechoslovakia, September 12, 1923.] PREFACE Meteoritics is the study of the only tangible entities that reach us from outer space. Except for the meteorites, scientists have to depend entirely on studies of some form of _radiation_ for all their knowledge of the wider cosmos lying outside of the atmosphere of the earth. And none of the radiations reaching us from various sources afar can be held in the hand for examination. Each type of radiant energy incident upon our earth—whether that energy be light from the sun or from the more distant stars or the galaxies, or the reflected light from the planets and moons of our Solar System, or the less familiar forms of radiation, such as radio waves and cosmic rays—must be measured and permanently recorded by complicated instruments. Often the results given by even the most sensitive and tractable of these scientific robots turn out to be exceedingly difficult for man, their master, to interpret. But the meteorites require no such temperamental instruments for their measurement. They are themselves a permanent record. They can be weighed, sectioned, and polished. They can be studied chemically, microscopically, and radiometrically. In fact, they can be investigated _directly_, just as they are themselves, in our hands, by any method modern science may be clever enough to devise. This is why, now with the world’s attention drawn to ambitious plans for the exploration of the cosmos, meteors and meteorites are of increasing interest and importance.