685 
The tables of the planets and especially those of Jupiter, which 
are reproduced and examined in the latter work, show how highly 
developed the methods of the Babylonian astronomy of those centuries 
were, with a character of their own differing completely from the 
contemporaneous Greek and from modern astronomy. The astronomers 
of Babylon knew not only the regular alternation of direct and 
retrograde motions of the planets in each synodic period, but they 
also knew that besides this they do not circulate uniformly in the 
ecliptic. The calculation of this variable velocity, a consequence of 
the elliptic motion, was for the Greek astronomers a geometric 
problem, which they solved by excentric circles and goniometric 
functions (chords). The Babylonians endeavoured to achieve the same 
result by purely arithmetical methods. The chief reason of this 
difference was, undoubtedly, that the Babylonian science, being, as 
a part of the general religious teaching, the duty of the priest, had 
no occasion to develop new ideas regarding the position of the 
celestial bodies in space; its object could, therefore, be no other 
than by certain mathematical methods to transfer as well as possible 
to future years, the regular return of periods and variations from 
the previously observed places in the heavens. 
For Jupiter, Kuverer found three kinds of tables. They all contained 
originally (even though only fragments are left), in five columns 
beside each other, the heliacie rise, the first station, the opposition, 
the second station and the heliacie setting for all the successive 
periods of Jupiter. For each of these phenomena is given: the year 
(according to the Seleucidian era, which begins 312 B. C.), date 
(month and day), longitude of the planet, (sign of the zodiac, degrees, 
minutes). They differ in the way in which the figures in the tables 
are calculated; the first kind is the roughest, the third the most 
accurate. If the planet described a circular orbit the construction 
of such a table were simple enough: each opposition would take 
place 398,884 days after the previous one and at a longitude 
33°8'37"5 larger, and the same interval would hold good for the 
other special phenomena. In consequence of the elliptical motion 
the intervals are not always of the same length. Now in the tables 
of the first kind Kue.rr found the following arithmetical process 
made use of to find the longitude of the planet. In the region of 
the ecliptic from 240° to 85° longitude (80° m to 25° 1) 36° is 
taken as the synodie arc; from 85° to 240° an are of 30° is taken. 
If a synodie are falls partly in one and partly in the other region, 
a value between these two is taken. If, for instance, one of the 
phenomena (e.g. the opposition) falls in a certain year on the 
