PTOLEMY. 
time, and shows how different those places 
were then, from what they had been in the 
times otTimociiaris, Hipparchus, Aristillus,' 
Calippus, and others : he then lays down a 
Catalogue of the stars in each of the north- 
ern constellations, with their latitude, Ion- 
gitude, and magnitudes. 
' In the eighth book he gives a like cata- 
logue of the stars in the constellations of 
the southern hemisphere, and in the twelve 
signs or constellations of the zodiac. This 
is the first catalogue of the stars now ex- 
tant, and forms the most valuable part of 
Ptolemy’s works. He then treats of the ga- 
laxy, or milky- way; also of the planetary 
aspects, with the rising and setting of the 
sun, moon, and stars. 
In the ninth book he treats of the order 
«f the snn, moon, and planets, with the pe- 
riodical revolutions of the five planets ; then 
he gives tables of the mean motions, begin- 
ning with the theory of Mercury, and show- 
ing its various phenomena with respect to 
the earth. 
The tenth book begins with the theory of 
the planet Venus, treating of its greatest 
distance from the sun ; of its epicycle, ec- 
centricity, and periodical motions ; it then 
treats of the same particulars in the planet 
Mars. 
The eleventh book treats of the same 
circumstances in the theory of the planets 
Jupiter and Saturn. It also corrects all the 
planetary motions, from observations made 
from the time of Nabonazar to his own. 
The twelfth book treats of the retrogres- 
sive motion of the several planets, giving 
also tables of their stations, and of the 
greatest distances of Venus and Mercury 
from the snn. 
The thirteenth book treats of the several 
hypotheses of the latitude of tlie five pla- 
nets ; of the greatest latitude or inclination 
of the orbits of the five planets, which are 
computed and disposed in tables ; of the 
rising and setting of the planets, with tables 
of them. Then follows a conclusion or 
winding-np of the whole work. 
This great work of Ptolemy will always 
be valuable on account of the observations 
he gives of the places of the stars and pla- 
nets in former times, and according to an- 
cient philosophers and astronomers, that 
were then extant; but principally on ac- 
count of the large and curious catalogue of 
tlie stars, which being compared with their 
places at present, we thence deduce the 
arue quantity of their slow progressive luo- 
voL. y. 
tion according to the order of the signs, or 
of the precession of the equinoxes. 
Another great and important work of 
Ptolemy was, his Geography, in seven 
books ; in which, with his usual sagacity, he 
searches out and marks the situation of 
places according to their latitudes and lon- 
gitudes ; and he was the first that did so. 
Though this work must needs fall far short 
of perfection, through the want of necessary 
observations, yet it is of considerable me- 
rit, and has been very useful to modem 
geographers. Cellarius, indeed, suspects, 
and he was a very competent judge, that 
Ptolemy did not use all the care and appli- 
cation which the nature of his work re- 
quired ; and his reason is, that the author 
delivers himself with the same fluency and 
appearance of certainty, concerning things 
and places at the remotest distance, which 
it was impossible he could know any tiling 
of, that he does concerning those which lay 
the nearest to him, and fall the most under 
his cognizance. Salmasius had before made 
some remarks to the same puipose upon 
this work of Ptolemy. The Greek text of 
this work was first published by itself at 
Basil, in 1533, in quarto : afterwards with 
a Latin version, and notes, by Gerard Mer- 
cator, at Amsterdam, 1605; which last 
edition was reprinted at the same place, 
1618, in folio, with neat geographical tables 
by Berlins. 
Other works of Ptolemy, though less 
considerable than these two, are still extant. 
As, “ Libri qnatuor de Judiciis Astrorum,’* 
upon the first two books of which Cardan 
wrote a commentary ; “ Friietus Librorutn 
suornui,” a kind of supplement to the former 
work; “ Recentio Chronologica Regum;’* 
this, with another work of Ptolemy, “ De 
Hypothesibus Planetarnm,” was published 
in 1620, 4to,, by John Bainbridge, the Sa- 
vilian Professor of Astronomy at Oxford, 
and Scaliger, Petavius, Dodwell, and the 
other chronological writers have made great 
use of it ; “ Apparentiae Stellarum Inerran- 
tiiun ;” this was published at Paris by Pe- 
tavius, with a Latin version, 1630, in folio; 
but from a mutilated copy, the defects of 
which have since been supplied from a per- 
fect one, which Sir Henry Saville had com- 
municated to Archbishop Usher, by Fabri- 
cius, in the third volume of his Bibliotheca 
Groeca ; “ Elementaruni Harmonicarum li- 
bri tres,” published in Greek and Latin, 
with a Commentary, by Porphyry, the phi- 
losopher, by Dr. Wallis, at Oxford, 1682. 
K k 
