The comet had passed perihelion on Feb. 27, and was seen at one place in New England on the 28th, close to the sun. During its brightest period it was visible in the daytime at one place in this section of the country from 7.30 A.M. to 3 P.M., when clouds intervened; and in Mexico from 9 A.M. till sunset. It passed but about 90,000 miles from the sun’s surface and through more than 300,000 miles of the sun’s corona, its velocity then being 350 miles per second. Its head was small, but its tail large and brilliant. The total light emitted by the meteor is stated by Prof. Loomis to have been equal to that of the moon at midnight in a clear sky. By the telescope its tail could be traced over a computed distance of 108,000,000 miles, so that had it been pointed towards the earth it would have passed through the planet’s atmosphere and 15,000,000 miles beyond. The professor names as its notable characteristics “its small perihelion distance, nearly as small as is physically possible, and its prodigious length of tail.” It continued visible into the following month. It is known in the books as “the great comet of 1843,” but for reasons which will appear, it might well be called “the Harvard comet.” The friends of the young institution at Cambridge perceived that the moment was opportune for an appeal to the moneyed public. The prevalent curiosity as to the visitor could not be gratified by the observers at the Dana house. They had no instruments fit for the occasion. An altitude-and-azimuth instrument, which had been used in the state survey of 1831, was borrowed and mounted in the cupola, and thus, on March 9, an observation was first made; but nothing came of the endeavor, it being found impossible to secure permanent adjustments. The next thing done was to call a meeting of citizens in Boston. The chairman was Hon. Abbot Lawrence. Addresses were made by Hon. John Pickering, Prof. Benjamin Peirce, Hon. William Appleton and Hon. S. A. Eliot. A financial committee was appointed, and subscriptions to the amount of $25,000 were obtained in Boston, Salem, New Bedford and Nantucket. Thus encouraged, the official board of the college negotiated for the purchase of the best telescope that could be produced in Europe, a refractor of 15 inches aperture, equatorially mounted, the makers being Merz & Mahler of Munich. The spot for building a massive stone supporting pier on Summer House hill was fixed Aug. 12, 1843, and ground was broken for the work on Aug. 15.