378 Chronicles of Science. [July, 
tion may have the effect of shifting the radiant pot more than 17°. 
. In future therefore it will be necessary to note the hour and the 
minute of each observation made on a falling star. 
Sir John Herschel has been engaged, since he sent to the Astro- 
nomical Society his synoptic catalogue of stars observed by Sir 
William Herschel, in forming a general digest of all the recorded 
measures of all known double stars—a task which “he hopes to leave 
in such a state of forwardness as will ensure its completion by some 
other hand.” While engaged on this task, he has been led by the 
coincidence, or near coincidence, of the measures taken by Sir 
William with those of stars observed by others, to the identification, 
more or less probable, of a considerable number of these stars with 
those subsequently measured. He supplies a list of the objects in 
question, judging “that information of this kind cannot but prove 
interesting to observers engaged in the measurement of double stars.” 
In the progress of the work he has been led to the detection of a 
somewhat formidable list of errata in the printed catalogue. We 
should recommend those who possess or make use of the catalogue 
to pay attention to these errata, some of which are important, and, if 
uncorrected, likely to cause the observer considerable waste of time. 
Mr. Key supplies an interesting paper on the planetary nebula 
45 H Geminorum. This nebula was discovered by Sir W. Herschel 
in 1787, and is described by him as “a star of the ninth magnitude, 
with a pretty bright nebulosity equally dispersed all round.” The 
younger Herschel describes it as “a star of the eighth magnitude, 
exactly in the centre of an exactly round bright hemisphere 25” in 
diameter.” Lord Rosse gives an account of the same object in the 
‘Philosophical Transactions, 1850. He saw it as a nebulous star with 
a black patch close to it on the preceding side, a less luminous space 
somewhat unequal in breadth surrounding the nucleus, and a lumi- 
nous ring at some distance; this ring being of less breadth on the 
following side. Mr. Lassell’s drawing of the object, in 1862, repre- 
sents a star in the centre of a planetary disc, surrounded by a non- 
luminous space, and, at some distance, by a luminous ring of consi- 
derable breadth. He adds that “he can see no trace of the dark 
patch of Lord Rosse’s drawing near the bright centre.” Mr. Key, 
using an 18-inch silvered-glass reflector 10 feet in focal length (of 
his own make), finds the present appearance of the object to be dif- 
ferent. It appears as a bright but somewhat nebulous star, closely 
surrounded by a dark ring; this again is surrounded by a luminous 
ring; then comes an interval much less luminous, and finally, at 
some distance, an exterior luminous ring. The whole is almost 
exactly symmetrical, though not quite so; the dark space between 
the two bright rings being darker on the north following side, and 
the preceding side of the whole object is rather fainter than the rest. 
Of the two luminous rings the inner is considerably the brighter. 
