SCIENTIFIC SUMMARY 
QUARTERLY RETROSPECT. 
ASTRONOMY. 
SMALL telescopic comet was discovered by Schwabe, at Athens, on 
July 2, and, a few hours later, at Marseilles, by Mr. Tempel. 
Subsequent observations and calculations proved that it passed its peri- 
helion on June 22. It continued all along very faint, and was only 
visible in good telescopes. Its least distance from the sun was about 
ninety-five millions of miles — almost identical with the earth’s mean 
distance from the central body. We have not seen it noticed that the 
orbit of this comet bears some resemblance to one discovered at 
Paris, on September 2, 1698. The direction of motion, the inclination to 
the ecliptic and the longitudes of the perihelion and node agree pretty well, 
and the least distance from the sun is not very dissimilar. The comet of 
1698 is, however, stated to have been as bright as a star of the second or 
third magnitude. 
A second and much brighter comet was discovered on July 18, at mid- 
night, at the Cambridge (United States) Observatory, in the constellation 
of Camelopardalus. It was independently detected at Florence, on 
J uly 24, and, on the following night, at Rome, by Professor Rosa. On 
the latter day it is described as being round, with a nebulosity of from 
three to four minutes in diameter and a distinct nucleus. Although almost 
circular, it was slightly dilated in the direction of the sun. No tail was 
visible in the comet-seeker, although with the naked eye one was faintly 
perceptible. On August 3, wdien first seen by the uniter, the comet was 
plainly visible to unassisted vision, and a slender tail was distinctly seen 
in the finder of the telescope. The nucleus was bright, and a well-defined 
fan-light was seen proceeding from one of the sides, which was almost 
at angles with the tail. On August 19 the comet had become a very con- 
spicuous object in the Northern hemisphere and the tail could be traced 
with the naked eye for a distance of eight or ten degrees from the head. 
The luminous sector had, however, disappeared, and an exceedingly bright 
jet of cometic matter lay in the contrary direction to the tail. At mid- 
miglit of August 24, the luminous sector again made its appearance, and a 
faint envelope was suspected as surrounding that part — a bright jet passed 
across the fantail from the nucleus, lying almost at right angles to the 
tail, which latter was as slender as on former occasions, and was 
separated from the head by an almost dark space. On August 25, at 
