270 
G. Tliibaut —Vardha Mihira’s Panchasiddhdnti/cd, [No. 2, 
Lanka while the rule of Varaha Mihira is, as we have seen, meant to 
give their mean places at noon. We therefore have to deduct frcm the 
mean place of the sun as found hitherto his mean motion for half a day, 
in order to obtain his mean place on the preceding neon. This mean 
motion for a day is 
800 
292207 
half of which is 
400 
292207 ’ 
Combining this 
subtractive 
442 
292207 
quantity with the one found above 
42 \ 
292207 ) 
we get 
the exact quantity stated in Yaraha Mihira’s rule. The 
result has therefore justified the small assumptions made in the calcula¬ 
tion of the ahargana ; the latter will moreover receive additional con¬ 
firmation from the rules about the mean places of the moon and the 
planets which will be discussed later on. 
The period of 800 years comprising 292,207 savana days whereby 
to calculate the mean place of the sun is of frequent occurrence in Indian 
astronomical writings and tables. It is employed by Brahmagupta in the 
Khanda-khadya. It is found in the Siamese astronomical rules which 
became known in Europe as early as 1688 and were first interpreted by 
Cassini. It is likewise used in the astronomical tables* sent to France by 
the Pere Patouillet and explained by Bailly in his Traite de I’Astronomie 
Indienne et Orientale, (p. 54 ; Discours preliminaire, p. xi). 
The verse which in the Panchasiddhantika follows next on the one 
explained above runs as follows : 
(In the first line we have to read ; in the second line, as will 
appear from the calculation, 5 I’eads'^^^f^^o.) 
“ Multiply (the ahargana) by 900,000, deduct 670,217 and divide 
by 24,589,506 ; the result is the mean place of the moon.” The general 
rule about the mean places of the moon which is contained in this 
verse is easily explained from the statements on the yuga of the Surya 
Siddhanta which we have had occasion to consider. The ynga com¬ 
prises 180,000 years. Multiplying these by 12 and adding the intercalary 
months we have 2,226,389 lunar synodical months. Again adding 
to these the 180,000 revolutions of the sun we get 2,406,389 as the 
number of the sidereal revolutions of the moon which take plaee in one 
yuga. (Dividing by the last number the savana days of the yuga we 
find as the length of the sidereal month 27^ 7^ 43' 12'60". The length 
of the sidereal month of the known Surya Siddhanta amounts to 27^ 7^ 
43' I2’64"). From the fact of 2,406,389 sidereal revolutions of the moon 
