Referring to the general descriptions which had been published in scientific journals and elsewhere of the appearance of this comet, the author pointed out,—1st, That the colour which had been attributed to it was merely the adventitious tint due to the twilight atmosphere through which it was seen. 2dly, That what had been described as the nucleus of the comet, and of so many thousand miles in diameter, nine days before the perihelion passage, was merely the head, composed of the same light, vaporous transparent matter as the tail; and subject to the same remarkable compression and conden-sation on approaching the sun.