COMET 1884 b.—M. Trépied further writes with respect to his observations of the comet discovered by Mr. Barnard:—“I hope you will favourably receive some remarks on the subject of your last article on the Barnard Comet. You say that it would not be prudent to pronounce upon the nature of the orbit on account of the uncertainty which seems to attach to the observations at Algiers. There was in fact an error committed on the first day, in the identification of the star of comparison, but that error was rectified almost immediately, and I am able to state that the verification to which I subsequently submitted that star (B.A.C. 5457) leaves no doubt as to the legitimacy of the identification. But I wish especially to remark that amongst the published orbits is one in which the observations at Algiers have had no part; it is that calculated by Chandler on the observations of July 16, 21, and 28.” M. Trépied suggests that the conjecture of Prof. Weiss as to the nature of the orbit rested not only on the differences in the mean place, but on the agreement of his own elements with those of Chandler. We are now aware, however, as was mentioned last week, that the apparent deviation from parabolic motion was caused by error in the position published for the night of discovery, and that M. Trépied's observations (the comparison star having been identified) prove very exact. The doubt we expressed was occasioned by the large corrections given in the circular of the Astronomische Nachrichten.