1884.] G. Tlii])aut —Varalia Mihira's VancliasvIdJidntiJcd. 
293 
the mean place of the moon as found from the general rule. This is as 
much as saying that - ° = O'7365'" for each day of the ahargana are 
4ooo 
to be deducted. Multiplying this quantity by the duration of the 
periodical month as stated above (27*^^ 7^ etc.) we obtain 20T218'". So 
many seconds of the circle are passed through by the moon in 36*65'". 
We add the latter quantity to the duration of the month and thus 
obtain 27^^ 7^^ 43' 12*65'", which is almost identical with that duration of 
the sidereal month which results from the elements of the published 
Siirya Siddhanta and differs very little only from the duration of the 
month presupposed by the Siirya Siddhanta of the Pahchasiddhantika. 
Bailly supposes that that estimation of the month which results from 800 
revolutions being considered equal to 21,857 days was the original one, 
and that the stated correction was added later for the purpose of bringing 
about an equality between the results of the tables of Narsapur and the 
tables of Krishnapur (which are likewise described by Bailly, Traite, 
etc., p. 31^’.). But matters have doubtless to be explained differently. 
The author of the tables of ISTarsapur was acquainted with the Siirya 
Siddhanta from which he derived his knowledge of the length of the 
sidereal month. He, however, aimed at replacing the inconveniently 
big numbers of the Siirya Siddhanta by smaller ones—in the same way 
as Varaha Mihira does in his account of the Siirya Siddhanta, went, 
however, a step further than the latter astronomer by reducing the 
period of 900,000 revolutions to its 1125th part, i. e., 800 revolutions. 
Dividing the 24,589,506 days of the former period by 1,125 we get 
21857 + 
381 
1125' 
The moon’s mean place is then calculated at first 
without the fraction being taken into account; but the error arising 
from this neglect is too considerable to be neglected, and so the above 
stated correction is applied finally.—We have to account in an analogous 
manner for the origin of the correction of the sun’s mean place which 
the tables of Harsapur apply (Bailly, p. 54). The period comprising 800 
revolutions of the sun which is employed there immediately presupposes 
a year of 365^^ 6^ 12" 36" while the year of the Surya Siddhanta is longer 
by 0*56". To make up for this difference 2" for each period of 87 years 
are dedueted from the sun’s mean place as calculated from the 800 year 
period. For if the year has been estimated 0*56" short of its real length 
the error amounts in 87 years to 48*7"", and in so much time the sun passes 
through two seconds of the circle. It thus appears that here again the 
correction had not the aim of reconciling two sets of astronomical tables 
but was contemplated by the author of the Narsapur tables at the out¬ 
set. 
