330 Scientific Intelligence. 
then, that this comet is a new one, whose orbit has never before been 
computed. 
The Comet, as seen at the Observatory of Harvard College, Cam- 
bridge, Muss. Communicated by G. P. Bonn, Director.—The comet was 
first seen at the observatory of Harvard College in the early twilight, on 
the evening of Tuesday, July 2d. The sky was clouded on the Ist and on 
the 30th. On Saturday the 29th of June the air was hazy, preventing 
the usual sweeping for comets, although observations near the meridian 
were prosecuted until about 11" p.m. Had the sky been clear, the tail of 
the comet would probably have been seen. A day or two previous, the 
western twilight had been explored with an opera-glass; but at this time 
only the upper part of the tail could have been in sight, and it must have 
been too faint to attract notice. The condition of the theory of cometary 
formation makes it very desirable that astronomers should devote more 
attention than they have hitherto been accustomed to do to the accurate 
delineation of the curve of the tail among the stars. The present oppor- 
tunity has been improved at the observatory of Harvard College, by 
making careful tracings of the boundaries of the rays through their entire 
extent upon star-charts. The Uranometria Nova of Argelander was 
found to be especially convenient for the purpose, both from the exact- 
ness of the projection, and the care taken in giving the proper magnitudes 
to the stars, which greatly facilitates their identification. An uninter- 
rupted series of clear nights, from the 2d of July to the present time, has 
very much favoured us in preserving the continuity of the phenomena, 
which is a condition of the utmost importance for their future discussion. 
The suddenness of the apparition of the comet in northern latitudes 
was one of the most impressive of its characteristics. On the 2d of July 
after the twilight had disappeared, the head, to the naked eye, was much 
brighter than a star of the first magnitude, if only the effective impres- 
sion be taken into account, although as to intensity it was far inferior to 
a Lyre, or even to # Urs Majoris. I should describe the head as nearly 
equal in brightness to that of the great comet of 1858 between the 30th 
of September and the 5th of October; it should be considered however 
that the present comet was better situated, from its higher position above 
the horizon at the end of twilight. 
The aspect of the tail suggested a resemblance to the comet of March 
1843. It was a narrow, straight ray projected to a distance of one hundred 
and six degrees (106°) from the nucleus, being easily distinguishable quite 
up to the borders of the milky way. ‘The boundaries for the most part 
were well defined and easily traced among the stars. It was not until 
after two or three hours of observation that I could gain a clear compre- 
hension of the structure of the tail or tails as they presented themselves 
to the naked eye and through a small opera-glass. It was then evident 
that a diffuse, dim light, with very uncertain outlines, apparently com- 
posed of hazy filaments, swept off in a strong curve towards the stars in | 
the tail of Ursa Major—the southern edge directed as low as towards 
Mizar. This was evidently a broad curved tail, intersected on its curved 
side at the distance of a few degrees from the nucleus by the long straight 
ray which at the first glance, from its greatly superior brightness, 
seemed alone to constitute the tail. The two were in fact counterparts of 
the principal tail and the supplementary rays of the great comet of 1858, 
with this remarkable difference, that in the latter the straight rays were 
so far inferior in brightness to the curved tail as to have been recognised 
at only three observatories—those of Poulkova, Gottingen, and Cambridge, 
U.S.—while with the present comet the predominating feature was the. 
straight ray, to which the curved tail seemed scarcely more than a wisp- 
like appendage. 
