o7 



SOLAR ECLIPSE. 



SOLAU SYSTEM. 



659 



who proceeded to the countries of Northern Europe for the purpose of 

 observing the phenomenon. According to Mr. Lassell, they were of a 

 most brilliant lake colour, a splendid pink, quite defined and hard. 

 Mr. Dawes remarked a bluntly triangular pink body suspended, as it 

 were, in the corona, and the distance of which from the moon's limb 

 was observed to increase as the moon continued to advance over the 

 solar disc. The isolated patch of light was also seen by the greater 

 number of the observers of the eclipse. 



M. Moesta, who observed the eclipse of 1853, remarked on the same 

 side of the corona, with a very conspicuous protuberance, two darker 

 spots, of a form approaching to a square, in apparent contact with the 

 moon's limb. They seemed to indicate an interruption of the corona, or 

 rajther two apertures through which the dark ground of the heavens 

 was visible. Their height above the moon's limb was estimated to 

 amount to 1'. 



The protuberances which appeared during the total eclipse of 1860 

 resembled in their general features those observed on previous occa- 

 sions. One of them appeared isolated from the moon's limb, but was 

 seen to approach the latter as the moon advanced over the solar disk. 



The question has been much discussed, whether the red prominences 

 seen during a total eclipse of the sun belong to the sun or the moon. 

 The observations of the total eclipse of 1842 seemed to indicate that 

 they are appendages of the sun, for it was remarked by several of the 

 observers, that the protuberances on the western limb of the moon 

 gradually increased in magnitude as the moon advanced over the solar 

 disc, while those on the eastern limb similarly diminished in size, con- 

 sequences which would necessarily result from the protuberances being 

 situate behind the dark body of the moon. This view of the origin of 

 the protuberances was also strengthened by similar observations made 

 during the eclipse of 1851 ; but it was established beyond all doubt 

 by the observations of the eclipse of 1860. On the lout-mentioned 

 occasion it was remarked by several observers, that as the moon ad- 

 vanced over the solar disk, the protuberances on the eastern limb of 

 the moon which first came into view, gradually diminished in size, 

 while those on the western limb, which at the commencement of the 

 totality were invisible, gradually increased in dimensions. This in- 

 teresting circumstance has also been indicated by photographs of the 

 protuberances taken by Mr. Warren De La Rue, and by the Italian 

 astronomer Professor Secchi. 



Besides the protuberances which form so conspicuous an object 

 during the totality of an eclipse, there lias been generally observed at 

 the parts of the moon's limb where the solar light disappears, and 

 again at the parts where it reappears, a long red streak of light, appa- 

 rently of the same physical nature as the protuberances, and tending 

 to support the opinion that the whole surface of the sun is enveloped 

 in such a substance. 



Attempts have been made to connect the rose-coloured protuberances 

 with the solar spots, but the results of a careful comparison of the two 

 classes of phenomena do not seem to indicate the existence of any 

 physical relation between them. Other observers have endeavoured, 

 but with no better success, to account for the protuberances by means 

 of the faculic of the solar disk. 



The most probable view of the nature of the more important phe- 

 nomena which reveal themselves during a total eclipse of the sun, is 

 that the corona represents an atmosphere about the sun, and that the 

 protuberances are emanations from a substance enveloping the surface 

 of the sun, and somehow connected with the generation of the solar 

 light and heat. 



We shall conclude this article with adverting briefly to a phenomenon, 

 apparently originating in an optical delusion, which has been sometimes 

 remarked on the occasion of total or annular eclipses of the sun. In 

 the case of an annular eclipse, the western limb of the moon, previous 

 to the formation of the annulus, exhibits an indented appearance, 

 resembling a succession of beads. Almost immediately the beads 

 become elongated, assuming the aspect of long black parallel streaks, 

 uniting the limbs of the sun and moon. In the next instant these 

 lines give way, as if they had been snapped asunder by the eastward 

 motion of the moon, and the annulus then appears completely formed. 

 The same succession of appearances has been witnessed when the 

 eastern limb of the moon is approaching the corresponding limb of 

 the sun. Phenomena of this nature were witnessed during the 

 eclipses of 1724, 1737, 1748, and 1791. Nicolai also observed a similar 

 appearance very distinctly during his observation of the annular 

 eclipse of September 7, 1820, at Manheim. He remarked that about a 

 second before the annulus was formed, the fine curve of the moon's 

 disk, then in contact with the sun's limb, appeared broken into several 

 parts ; and in a moment these parts flowed together like drops of water 

 or quicksilver near each other. De Zach, who observed the same 

 eclipse at Bologna, also remarks that before the contact of the two 

 limbs was effected, there was visible, not a continuous thread of light, 

 but a number of luminous points, resembling a row of so many pearl 

 beads, -separated by dark intervals. But the most vivid description of 

 the phenomenon has been given by Francis Baily, who observed the 

 annular eclipse of May 15, 1838, at Jedburgh, in the south of Scotland. 

 A-t. Soc.,' vol. x.) When the cusps of the sun, previous to 

 the formation of the annulns, were about 40 asunder, a row of lucid 

 points, like a string of beads, irregular in size and distance from each 

 other, suddenly formed round the part of the circumference of the 



ARTS AND SCI. DIV. VOL. Til. 



moon that was about to enter on the sun's disk. Its formation was so 

 rapid that it presented the appearance of having been caused by the 

 ignition of a fine train of gunpowder. His impression was, that the 

 annulus had just been formed, but to his great surprise he found that 

 the luminous points, as well as the dark intervening spaces, increased 

 in magnitude, some of the contiguous ones appearing to run into each 

 other, like drops of water ; for the rapidity of the change was so great, 

 and the singularity of the appearance so fascinating and attractive, that 

 the mind was for the moment distracted, and lost in the contemplation 

 of the scene, so as to be unable to attend to every minute occurrence. 

 Finally, as the moon pursued her course, the dark intervening spaces 

 (which at their origin had the appearance of lunar mountains in high 

 relief, and which still continued attached to the suu's border) were 

 stretched out into long, black, thick, parallel lines, joining the limbs of 

 the sun and moon, when all at once they suddenly gave way, and left 

 the circumference of the sun and moon in those points, as in the rest, 

 comparatively smooth and circular ; and the moon perceptibly advanced 

 on the face of the sun. The same appearance, although in a reverse 

 order, was witnessed on the breaking up of the amuilus. While the 

 limb of the - moon was yet at some distance from the margin of the 

 solar disk, a number of long, black, thick, parallel lines suddenly darted 

 forward from the moon, and joined the two limbs as before. ' As these 

 dark lines got shorter, the intervening bright parts assumed a more 

 circular and irregular shape, and at length tesaiiuatcd in a fine curved 

 line of bright beads, as at the commencement, till they ultimately 

 vanished, and the annulus ceased to exist. 



The' phenomenon alluded to in the foregoing description, which has 

 received the appellation of " Baily's beads," has been carefully sought 

 for on the occasion of all the total and annular eclipses which have 

 been observed in recent times, but no confirmation of its existence has 

 been obtained except in a few doubtful instances. The most probable 

 explanation of its origin is that which supposes it to be due to some 

 imperfection connected with the optical qualities of the telescope. 



SOLAH SYSTEM. We have given the elements of the planetary 

 motions minutely in the several articles MERCURV, VENUS, &c., together 

 with such physical peculiarities as belong to them severally, and inde- 

 pendently of the System ; the general phenomena of their motions 

 have been deduced from the great principle of GRAVITATION; their 

 history, as far as it is in the plan of this work to give it, has been 

 treated in ASTRONOMY. It remains to bring together the dimensions 

 of the various parts of the System, and to notice such points as could 

 not properly find a place under any of the heads just mentioned. 



By the Solar System is meant that collection o bodies which 

 contains the Sun, the planets which revolve rouud him, their satellites, 

 and such periodic comets as have had their returns successfully pre- 

 dicted. The system of the ancients includes the Earth as a fixed 

 centre, with the Moon, Mercury, Venus, the Sun, Mars, Jupiter, and 

 Saturn. That of the moderns includes at this day the Sun as a govern- 

 ing body (but not as a fixed centre), Mercury, Venus, the Earth (with 

 the Moon), Mars, the group of minor planets (now amounting to sixty- 

 four),* Jupiter and four satellites, Saturn (with his triple ring) and 

 eight satellites, Uranus with four satellites, and Neptune with one 

 satellite, besides a considerable number of periodic cornets. The follow- 

 ing symbols are used to represent the ancient members of the system, 

 to which we add the received explanation, without expressing any 

 opinion about it : 



Q Sun. 



5 Mercury. 



? Venus. 



or $ Earth 



(modern). 

 ]) Moon. 



Mars. 



Jupiter. 



Saturn. 



The symbol for the Sun is all that modern abridgment has left 6f a 

 face surrounded by rays ; Mercury has the caducous, or rod, entwined 

 by two serpents ; Venus, a circular looking-glass with a handle ; the 

 Earth (a modern symbol) has a sphere with an equator, and also 

 (with some) an inverted symbol of Venus. Those who first used it 

 did not, we presume, know that they might be making a looking-glass 

 turned upside down represent their planet. The symbol of the Moon 

 is obvious ; Mars has what remains of a spear and shield ; Jupiter, 

 supposed to be a symbol of the thunder (arm and hand holding 

 thunder ?) ; Saturn, an altered form of a mower's scythe, the emblem of 

 time. But others have thought that Mercury was designated by 

 putting a and T together, the initials of orlkftuv; Venus, from the first 

 a"nd last letters of &a<r<t>iipos ; Jupiter, from the first and last letters of 

 Zfi/s. These signs are found on very old manuscripts and gems, 

 variously figured, but all with some general resemblance to the modern 

 printed forms. 



The four minor planets discovered about the beginning of the pre- 

 sent century were also designated by symbols. Vesta had for its 

 symbol @\ , or an altar with fire on it ; J uno was designated by a sceptre, 

 :f ; Ceres, by a reaper's scythe, J ; and Pallas by the head of a lance, 



* Since the article ASIF.ROIDS was written, eight additional members of the 

 minor planet-group have been discovered, namely : in 1859, Mnemosyne, at 



at Itaplf.*, I'V w uu&jjuiia , piuiici. ut, ui maiBvmtJ, uy .ti> icuipei. i IK: 



number of asteroids accordingly now (March, 1861) amounts to sixty-four. 



