691 
the calculation. Whereas in the four cases clerical errors of the 
Babylonian copyists are not impossible, the permanent deviation 
in the last 9 values points to an error of calculation, as, once an 
error has been made in the addition, this error is carried on in all the 
subsequent values. Probably (as may easily oceur in the Babylonian 
method of writing figures) the difference 50130 was read as 51 30, 
whereby all subsequent dates would become 1°28.15 too large. 
Il. 
We will now proceed to the calculation of dates in the Jupiter 
tables of the first and the second kind. Kverer has converted the data 
of table Sp. IT 101, the largest of the first kind, into Julian dates; 
if we take the successive differences between these, they vary so 
irregularly between 365 + 37 and + 29 days, that to search for 
the method of calculation seems indeed hopeless. If, however, guided 
by what we found in the tables of the third kind, we assume that 
a normal month of 30 days is used in the calculations all the time, 
a much greater order and regularity immediately appear in the 
differences. These differences, which in Table II are placed in the 
2nd column, show the same character as the differences of longitude: 
a number of times a greatest value of 48¢ alternates with a smallest 
one of 42¢, in the same intervals as for the longitude synodie ares 
of 36° and 30° alternate, while at the points of transition inter- 
mediate values appear (See table II p. 692). 
It is natural to assume the same method of calculation for these 
intermediate values as for those in, the longitude, viz. as long as the 
planet stands in the region of 30°, the time-interval 42¢ holds, and 
as long as it stands in the region of 36°, 48¢ holds. Then the number 
of days of the time-interval must always be exactly 12 more than 
the number of degrees of the synodic arc. The following list shows 
that this is not always the case. 
Second stationary point Heliacie setting 
Time-interval: 42 47 43 46 44 45 44 46 48 
Syn. arc +12: 43.3 45.9 434 451 43.9 44.9 438.2 45.8 42.4 
In the first case the cause of the difference is the synodic arc 
having been calculated wrong; to the starting point 0°25' Mm a synodic 
are of 30°5' belongs, so that the time-interval 42 is correct. But 
amongst the others there are 4 with deviations of 1 day. This, 
therefore, requires further elucidation, which was only found after 
44* 
