552 
POPULAR SCIENCE REVIEW. 
Cygni, that it is not the brightest stars which are always nearest to us ; 
only one of the latter, Alpha Centauri, having a considerable parallax. 
New Comets and Planets. — The second and third comets of 1863, discovered 
respectively by Klinkerfues and Respighi, were frequently observed during 
the months of April and May, but both became much fainter during the 
latter month. The first was a round nebula, which on April 20 was 
about 4' of arc in diameter ; the latter on April 26 was visible to the 
naked eye, with bright stellar nucleus, and a tail of a degree in length. 
The 78th planet, discovered by Dr. Luther on March 15 last, has received 
the name of Diana, and was of the 10th magnitude at that epoch. The 
planet (77) discovered by Peters in November last appears to have been 
unfortunate, and will with difficulty be refound, as no further observations 
have been taken, nor its elements computed. Another somewhat luckless 
planet (Leukothea) comes into opposition in November next, but will be 
of the last degree of faintness. M. Schubert, however, requests observers 
with proper means to pay particular attention to it, as he intends to inves- 
tigate the mass of Jupiter by it — an important object, which shows the 
utility of even those little bodies. 
Spots on Sun and Zodiacal Light. — Professor Wolf, whose labours in 
respect to the solar spots are so well known, gives further proofs of their 
periodicity, their relative numbers in the five years 1858 — 1862 being 
respectively 509 ; 96’4 ; 98 - 6 ; 77'4 and 59’4. He had previously deter- 
mined the maximum for 186C-2, and has thence deduced the mean 
declination variation for Prague and Munich. The connection between 
the Solar Spots and Northern Lights has been likewise satisfactorily 
established, the period of the first, which recurs every eleven years, agree- 
ing perfectly with that of the second. 
Eta Argils. — This celebrated variable star, which passes between the 
4th and 1st magnitude, and at its latter phase being brighter than 
any of the stars of the southern hemisphere, has likewise been investigated 
by Professor Wolf. He finds a period of 46 years. In the curve of 
brightness given by him, it passes from the 4th magnitude to the 1^ 
magnitude, then declines to the 2nd magnitude, after this increases 
to its greatest brightness in 23 years ; six years subsequently falls to the 
2nd magnitude ; whence in five years time it rises to 1^ magnitude, 
and then decreases to the 4th magnitude. 
Jupiter’s Satellites and the Pleiades. — It has frequently been argued 
whether Jupiter’s satellites are visible to the naked eye, and equally so as 
to the number of stars in the Pleiades visible under those circumstances. 
A member of the Astronomer Royal’s family instead of the ordinary six 
always sees seven, and in favourable weather as many as twelve, and this 
has been verified by actual mapping. Mr. Mason, on April 15, after 
gazing with great care at Jupiter, and taking every precaution, detected 
a luminous point close to the planet which was altogether independent of 
the radiations, and on looking through his telescope found the satellites 
clustered at the point which he had previously noticed. 
