Page 377 - 89 history of astronomy_opt
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peared, and the instrument was put out of
                                         use until 1903, when the present Astronomer
                                         Royal noticed that the irregularities could
                                         be allowed for, being due to that remarkable
                                         variation in the position of the earth’s axis
                                         included in circles of about six yards diame-
                                         ter at the north and south poles, discovered
                                         at the end of the nineteenth century. The
                                         instrument is now being used for investigat-
                                                           377
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