The Porto Rico Magnetic Observatory of the United States Coast and Geodetic Survey, temporarily established in February, 1903, in the basement rooms of the old abandoned Spanish fort (Isabel) at Vieques, on the Island of Vieques, Porto Rico, was removed to a new site during the first part of April, 1907. The occasion for the change in the location of the observatory was that the Insular Government required the entire fort for the installation of a public hospital.After a thorough examination and lnagnetic survey of the possible locations in the vicinity, a suitable site was found about ⅝ mile west of the old observatory (Fort Isabel). The erection of the special buildings required was begun the first of February, 1907, the work was completed under the supervision of Mr. W. B. Keeling (the present observer‐in‐charge), the variation instruments were installed, and records were being obtained on the 10th of April, 1907.