ASTRONOMY. 
410 
fine brilliant white, the /mailed dufky ; it appears with a 
power of 227. Dr. Herfchel meafured the diameter of 
this fine ftar, and found it to be 0 3553". 
The number of the liars appears to be immenfely great, 
a!mod infinite ; yet have adronomers long fince afcertain- 
ed the number of fuch as are vilible to the eye, which are 
much fewer than at fird light could be imagined. Of the 
3000 contained in Flamftead’s catalogue, there are many 
that are only vilible through a telefcope; and a good eye 
fcarcely ever fees more than a thoufand at the fame time 
in the cleared heaven; the appearance of innumerable 
more, that are frequent in clear winter nights, arilingfrom 
our fight’s being deceived by their twinkling, and from 
our viewing them confufediy, and not reducing them to 
any order. But neverthelefs we cannot but think the dars 
are alrnod, if not altogether, infinite. See Halley, on the 
number, order, and light, of the fixed dars, Phil. Tranf. 
No. ccclxiv. or Abr. vol. vi. p. 148. 
Riccioli, in his New Almaged, affirms, that a man who 
/hall fay there are above twenty thoufand times twenty 
thoufand, would fay nothing improbable. Foragood te¬ 
lefcope, directed indifferently to almotl any point of the 
heavens, difcovers multitudes that are loll to the naked 
eye ; particularly in the milky way. In the fingle conllel- 
lation of the Pleiades, indead of fix, feven, or eight, dars, 
feen by the bed eye, Dr. Hook, with a telefcope twelve 
feet long, told feventy-eight, and with larger glades many 
more, of different magnitudes. And F. de Rheita affirms, 
that he has obferved above 2000 dars in the fingle conftel- 
lation of Orion. The fame author found above 188 in the 
Pleiades. And Huygens, looking at the dar in the mid¬ 
dle of Orion’s fword, indead of one, found it to be twelve. 
Galileo found eighty in the fpace of the belt of Orion’s 
l'vvord, twenty-one in the nebulous dar of his head, and 
above 500 in another part of him, within the compafs of 
one or two degrees fpace, and more than forty in the ne¬ 
bulous dar Praefepe; but the more recent difeoveries 
of Dr. Herfchel have proved the fixed dars to be immenfe, 
their regions unbounded, and perhaps infinite! 
The appearance of new dars, and the changes which 
have happened in others, offer to the mind a phenomenon 
more furprifing, and lefs explicable, than almod any other 
in the fcience of adronomy. The firft change that is up¬ 
on record was about 120 years before Chrid, when Hip¬ 
parchus, difeovering a new dar to appear, was fird indu¬ 
ced to make a catalogue of the dars, that poderity might 
perceive any future changes of the like nature. In the 
year 1572, Cornelius Gemma, and Tycho Brahe, obfer¬ 
ved another new dar in the condellation Caffiopeia, which 
was likewife the occafion of Tycho’s making a new cata¬ 
logue. At fird its magnitude and brightnefs exceeded the 
larged of the dars, Sirius and Lyra; and even equalled 
the planet Venus when neared the Earth, and was feen in 
fair day-light. It continued fixteen months; towards the 
latter end of which it began to dwindle, and, at length, 
in March 1574, it totally difappeared, without any change 
of place in all that time. Leovicius tells us of another 
dar appearing in the fame condellation, about the year 
945, which refembled that of 1572; and he quotes ano¬ 
ther ancient obfervation, by which it appears, that a new 
dar was feen about the fame place in 1264. Dr. Keil 
thinks thefe were all the fame dar; and indeed the perio¬ 
dical intervals, or didance of time between thefe appear¬ 
ances, were nearly equal, being from 318 to 319 years ; 
and, iffo, its next appearance may be expended about 1890. 
Fabricius, in J596, difcovered another new dar, called 
the Jlelta mira, or ‘ wonderful ftar,’ in the neck of the 
Whale, which has fince been found to appear and difap- 
pear periodically, feven times in fix years, continuing in 
jts greated ludre for fifteen days together; and is never 
quite extinguifhed. Its courfe and motion are deferibed 
by Bulliald, in a treatife printed at Paris in 1667. Dr. 
Herfchel has lately, viz. inthe years 1777, 1778, 1779,and 
1780, made feveral obfervations on this dar, an account of 
which may be feen in the Phil. Tranf, vol.lxx. art. 21. 
Ill the year 1600, William Janfen difcovered a change¬ 
able dar in the neck of the Swan. It was feen by Kep¬ 
ler, who wrote a treatife upon it, and determined its place 
to be 16 0 18' Zd, with 55 0 30'or 32'north latitude. Ric- 
ciolus faw it in 1616, 1621, 1624, and 1629. He is pofi- 
tive that it was invifible in the lad years from 1640 to 1650. 
M. Caffini faw it ag.Sn in 1655 ; it increafed till 1660, and 
then grew le/’s, and at the end of 1661 it difappeared. In 
November 1665 it appeared again,and difappeared in 1681. 
In 1715 it appeared of the fixth magnitude, and has con¬ 
tinued fo ever fince. 
O11 June 20, 1670, another changeable dar was difco¬ 
vered near the Swan’s Head, by P. Anthelme. It difap¬ 
peared in October, and was feen again on March 17, 1671. 
On September 11, it difappeared. It appeared again in 
March 1672, and difappeared in the fame month, and has 
never fince been feen. Its longitude was i° 52'26" of 2%, 
and its latitude 47 0 25' 22" north. The days are here put 
down for the new dyle. 
In 1686, Kircher obferved % in the Swan to be a change¬ 
able dar; and, from twenty years obfervations, the period 
of the return of the (ame phafes was found to be 405 days; 
the variations of its magnitude, however, were fubje.ft to 
fome irregularity. 
In the year 1604, at the beginning of October, Kepler 
difcovered a new dar near the heel of the right foot of Ser-i 
pentarius, fo very brilliant, that it exceeded every fixed 
ftar, and even Jupiter in magnitude. It was obferved to 
be every moment changing into fome of the colours of 
the rainbow, except when it was near the horizon, when 
it was generally white. It gradually diminifhed, and dif¬ 
appeared about October 1605, when it came too near the 
Sun to be vjfible, and was never feen after. Its longitude 
was 17 0 40'of with i° 56' north latitude, and was 
found to have no parallax. 
Montanari difcovered two ftars in the condellation of 
Ship, marked 0 and 7 by Bayer, to be wanting. He faw 
them in 1664, but loft them in 1668. The ftar 0 in the 
tail of the Serpent, reckoned by Tycho of the third, was 
found by him of the fifth, magnitude. The ftar p in Ser- 
pentarius did not appear, from the time it was obferved 
by him, till 1695. The ftar T in the Lion, after difap- 
pearing, was feen by him in 1667. He obferved alfo that 
0 in Medufa’s Flead varied in its magnitude. 
M. Caffini difcovered one new ftar of the fourth, and two 
of the fifth, magnitude, in Cafliopea; alfo five new ftars in 
the fame condellation, of which three have difappeared; 
two new ones in the beginning of the conftellation Erida- 
mus, of the fourth and fifth magnitude; and four new 
ones of the fifth or fixth magnitude, near the north pole. 
He farther obferved, that the ftar, placed by Bayer near £ 
of the Little Bear, is no longer vilible ; that the ftar A of 
Andromeda, which had difappeared, had come into view 
again in 1695 ! that, in the fame conftellation, inftead of one 
in the Knee, marked v, there are two others come more 
northerly; and that | is diminiftied; that the ftar placed 
by Tycho at the end of the Chain of Andromeda, as of 
the fourth magnitude, could then fcarcely be feen; and, 
that the ftar which, in Tycho’s catalogue, is the twentieth 
of Pifces, was no longer vifible. 
M. Maraldi obferved, that the ftar x in the left leg of 
Sagittarius, marked by Bayer of the third magnitude, ap¬ 
peared of the fixth, in 1671 ; in 1676 it was found by Dr. 
Halley to be of the third; in 1692 it could hardly be per¬ 
ceived, but in 1693 and 1694 it was of the fourth magni¬ 
tude. In 1704 he difcovered a ftar in Hydra to be perio¬ 
dical ; its pofition is in a right line with thofe in the tail 
marked n and 7. The time between its greateft luftre, of 
the fourth magnitude, was about two years ; in the inter¬ 
mediate time it difappeared. In 1666, Hevelius fays he 
could not find a ftar of the fourth magnitude in the eaftern 
fcale of Libra, obferved by Tycho and Bayer; but Ma¬ 
raldi, in 1709, fays, that it had then been feen for fifteen 
years, fnialler than one of the fourth. See Elem. d’Aftron. 
P- 5N 
J. Goodrickes 
