SCIENTIFIC SUMMARY. 
447 
A new Planet, which, has been named Undina, has been simultaneously 
discovered by Peters, of Hamilton College, U. S., and Tietjens, of Berlin. 
Its magnitude is between the 10th and 11th, and it was first seen on the 
7th of July last. This is, then, the 100th or> according to those who 
believe in the existence of a planet within Mercury’s orbit, the 101st planet. 
Jupiter without his Satellites. — In our last number Mr. Proctor gave our 
readers ample notice of this singular phenomenon, and we are glad to find 
that many of them availed themselves of the opportunity noted. The editor 
of the Astronomical Register says that when the five black spots were pro- 
jected in the line of the belts, they gave one the idea of “a bar of printed 
music.” 
The Meteorlike Bodies near the Sun , which were described by Mr. Lowe 
and Mr. Bird, are alleged by Mr. C. L. Prince to have been nothing more 
than seeds of dandelion, floating through the atmosphere. The direction of 
these pseudo-meteors will be always found to coincide with that of the 
wind. 
Change of Focus in observing Stars. — The change of focus which is said 
to be requisite in the examination of stars widely separated in altitude, has 
been inquired into by Captain Noble, who lately laid a paper on the subject 
before the Boyal Astronomical Society. We conclude, from his observations, 
that in the finest state of the atmosphere the foci of all stars are identical. 
But he says that when, as in the normal state of things, there is an appreci- 
able amount of vapour near the horizon, a shortening of the focus of a 
telescope, directed to objects in its neighbourhood, may take place. — Vide 
Monthly Notices, June 14. 
The Expansion of Brass Pendula. — Major Tennant publishes a singular 
paper on this point. It would seem, from the evidence adduced by the author, 
that at a pressure of only five inches of mercury the coefficient of expansio 11 
of the brass pendulum must not only be increased, but appears to be 13 per 
cent, greater than ever before has been assigned to brass. 
Comets and Meteors. — In a paper on this subject, laid before the last 
meeting of the Astronomical Society, Mr. G-. J. Stoney, Secretary to the 
Queen’s University in Ireland, make the following interesting observations, 
which tend to show, as Schiaparelli has already pointed out, that there is a 
very natural relationship between comets and meteors. If interstellar space, 
external to the Solar System, be, as is most probable, peopled with innumer- 
able meteoric bodies independent of one another, a comet while outside the 
Solar System would in the lapse of ages collect a vast cluster of such 
meteorites within itself. Each meteorite which approached the comet would 
in general do so in a parabolic orbit ; and, if it came near enough to pass 
through a part of the comet, this parabolic orbit would, by the resistance of 
the matter of the comet, be converted into an ellipse. The meteor would 
therefore return again and again, and on each occasion that it passed through 
the comet its orbit would be still further shortened, until at length it would 
fall in, and add one to whatever cluster had been brought together by the 
previous repetitions of this process. In this way a comet, while moving in 
outer space, beyond the reach of the many powerful disturbing influences 
which prevail within the Solar System, would inevitably accumulate within 
itself just such a globular cluster of meteorites as the November meteors 
must have been before they became associated with the Solar System. 
