FOR the past ten years Prof. Bredichin lived in well-earned and dignified retirement in Saint Petersburg. After a life spent in directing, with consummate ability, the activities of the two great astronomical observatories of Moscow and Pulkova, he sought, while his energies were still vigorous, opportunity for cultivating with greater leisure those studies to which he had conspicuously devoted himself while in a public position. In the midst of that self-imposed work and at the zenith of his reputation, he has been removed by death to the profound loss of science in Russia. In 1857, he was called to fill the chair of astronomy in the University of Moscow, and with it to undertake the direction of the observatory. There he remained for thirty-three years, and devoted himself to astrospectroscopic observation, a subject new in Russia, to the study of variable stars, to gravity determinations by means of pendulum observations, and to a host of inquiries with which his name has long been connected. But most of all was his attention concentrated upon the formation and behaviour of comet tails, a subject which had practically lain dormant since Bessel's researches on the comet of Halley. Of this subject he never wearied, and shortly before his death he collected and published his more important papers bearing on this inquiry. This revision was perhaps the more necessary since photographs had revealed minuter details than could easily be detected in the ordinary telescope. It must be a matter of gratification to his numerous friends that the distinguished astronomer, in spite of bad health, was able to complete a task which had occupied him for so many years.