Excerpt from Measures of Proper Motion Stars Made With the 40-Inch Refractor of the Yerkes Observatory in the Years 1907 to 1912 The other list, forming Part I, includes all other stars for which prior observations with the micrometer have been made. Unfortunately the early work in this field is confined to a few observers, the principal ones being Otto Struve, Engelhardt, and Ball. For some of the other stars recent photographic positions have been found, but’ in most cases the time-interval is too short to give a very accurate value of the relative change. This objection will be removed by observations to be made hereafter.

The small stars from Zone 26 Degrees of the Oxford Astrographic Catalogue are taken from a list prepared by Mr. G. H. Hamilton of the University Observatory. This list gives the place, proper motion, and photographic magnitude of some fifty stars, principally below the magni tude limit in Argelander, from plates taken for the most part in 1907 and 1908, the proper motions being derived from a comparison with other plates made a few years earlier. All of these were put on the observing-list and, as far as possible, compared with one or more fainter stars in the field. In a few instances there were no comparison stars within the range of the micrometer.

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