THE MERIDIAN PHOTOMETER.—In vol. xxiii. of the Annals of the Harvard College Observatory, Prof. E. C. Pickering and O. C. Wendell give and discuss the observations made at Cambridge, U.S., with the meridian photometer during the years 1882-88. The observations relate principally to stars north of the declination - 40° Vol. xiv. of the Annals contained the results of observations of the brightness of stars made with a small meridian photometer. The present volume deals with the photometric measurements of somewhat fainter stars, made by means of a similar but larger instrument.