380 
POPULAK SCIENCE REVIEW. 
D’ Arrest four times in 1855 and 1856. With a telescope of four and a-half 
inch aperture, he describes it as “ very bright.” The writer of this notice 
stumbled upon it in the autumn of 1855, whilst searching for De Vico’s 
comet, and not finding it in any catalogue of nebulae, observed it as the 
object of which he was in search, as it bore an exact resemblance to a 
telescopic comet. It does not appear to have been looked for until the 
last few weeks, when to the great astonishment of astronomical observers, 
it was found to have completely disappeared , — not the slightest trace of 
it being visible in the most powerful telescopes, and even a star which 
was situated near it had dwindled from the tenth to the twelfth 
magnitude. Such a phenomenon as this completely alters all the former 
ideas and received hypotheses on the nature of nebulae, and from the 
reliable evidence on which it is founded precludes all chance of error in 
the observation. Whilst following this subject, the attention of those 
observers furnished with good telescopes might likewise be turned on the 
undermentioned nebulae, in which changes of lustre have been suspected 
by D’Arres. 
The “ faint nebula” Herschel, II., 99, is now (1855) of 1st class (bright 
nebulae). 
,, „ Herschel, II., 101, „ of 1st class „ 
The “ very faint nebula,” Herschel, III., 44, „ of 1st class ,, 
On the contrary : — 
The “bright Nebulae,” Herschel, I., 1, 23 and 104 are now faint nebulae. 
„ „ Herschel, I., 62, is scarcely perceptible. 
„ „ Herschel, I., 119, called “ very bright,” by Sir 
W., and “ bright” by Sir J. Herschel, is at present very faint. 
/Solar Eclipse of December Hist, 1861. — The total eclipse was observed 
pretty favourably in the south of France and Italy, and the north of 
Africa, hut the detailed accounts have not yet come to hand. Mr. 
Talmage, who observed the partial phase at Nice, states that Venus was 
visible (at 3h. 25m. p.m.), but that none of the brighter stars could he 
seen, and that there was a semi-circular streak of red light close to the 
limb of the sun, which gradually diminished to two abrupt points. M. 
Schmidt, the astronomer at Athens, was very unfortunate in endeavouring 
to catch a glimpse of the total phase (the sun setting fully eclipsed near 
Phlious), and his account of his expedition recalls the days of earlier 
Greece. On December 25th, he left Athens, travelled over the Corinthian 
Isthmus, where he saw the effects of the great earthquake of Aigion, and 
proceeded to Longopotamos over Kleona and Nemea to Hagios Georgion 
on the southern foot of the Trinkaranon. On the 30th he ascended 
Polyphengos to about 1,900 feet, but met with nothing hut rain, north 
wind, cold, and darkness. Haud ignarus mali, disco, &c. &c. The transit 
of Mercury across the Sun’s disc on November 11th, was observed at 
Adelaide (Australia), by Mr. Todd, as likewise at Victoria and Sydney. 
No phenomena were noticed. At Malta the heat of the sun was so great 
on that occasion, that Mr. Lassell was forced to construct a covering to 
shield him from the sun. He repeatedly fancied the planet to be elliptical, 
and when the limb of the planet touched the edge of the sun, the former 
took a “ pear-like” shape. The diameter of the planet as measured by 
