The Flammarion engraving is a wood engraving by an unknown artist, so named because its first documented appearance is in Camille Flammarion's 1888 book ("The Atmosphere: Popular Meteorology"). The wood engraving has often, but erroneously, been referred to as a woodcut. It has been used as a metaphorical illustration of either the scientific or the mystical quests for knowledge. Description The print depicts a man, clothed in a long robe and carrying a staff, who is at the edge of the Earth, where it meets the sky. He kneels down and passes his head, shoulders, and right arm through the star-studded sky, discovering a marvellous realm of circling clouds, fires and suns beyond the heavens. One of the elements of the cosmic machinery bears a strong resemblance to traditional pictorial representations of the "wheel in the middle of a wheel" described in the visions of the Hebrew prophet Ezekiel. The caption that accompanies the engraving in Flammarion's book reads: Attribution In 1957, astronomer Ernst Zinner claimed that the image dated to the German Renaissance, but he was unable to find any version published earlier than 1906. Further investigation, however, revealed that the work was a composite of images characteristic of different historical periods, and that it had been made with a burin, a tool used for wood engraving only since the late 18th century. The image was traced to Flammarion's book by Arthur Beer, an astrophysicist and historian of German science at Cambridge and, independently, by Bruno Weber, the curator of rare books at the Zürich central library. Flammarion had been apprenticed at the age of twelve to an engraver in Paris and it is believed that many of the illustrations for his books were engraved from his own drawings, probably under his supervision. Therefore, it is plausible that Flammarion himself created the image, though the evidence for this remains inconclusive. Like most other illustrations in Flammarion's books, the engraving carries no attribution. Although sometimes referred to as a forgery or a hoax, Flammarion does not characterize the engraving as a medieval or renaissance woodcut, and the mistaken interpretation of the engraving as an older work did not occur until after Flammarion's death. The decorative border surrounding the engraving is distinctly non-medieval and it was only by cropping it that the confusion about the historical origins of the image became possible. According to Bruno Weber and to astronomer Joseph Ashbrook,