290 
G, Tliibant —VardJia Mihira’s Fanchasiddhantikd. 
[No. 2, 
All identical rule for the calculation of the ahargana is not found 
anywhere else in Indian astronomy (as indeed it cannot be on account 
of the prevailing employment of the sidereal solar year) with one excep¬ 
tion. The rules of Siamese astronomy which have been alluded to above 
teach the calculation of the ahargana (or as it is called there horoconne—■ 
I quote from the account of Siamese astronomy given by Bailly in his 
Traite de T astronomie Indienne et Orientate) according to exactly the 
same method. The kshepa-quantities differ on account of the Siamese 
rules starting from a different epoch. 
But the proportions 
7 
228 
and 
n 
7C^ 
are both made use of. The use of the latter proportion is of no parti¬ 
cular interest; for the proportion is only approximately correct, and does 
not allow of any certain inference regarding the length of the synodical 
month beinsf founded on it. It is in fact—if I am not mistaken—occa- 
sionally used by karana writers who deal with the sidereal year only. 
But the former proportion as clearly pointing to a tropical solar year is 
noteworthy, all the more as the Siamese rules nowhere directly acknow¬ 
ledge the tropical year but uniformly employ the sidereal one. It did 
in fact not escape the attention of Cassini who inferred from it that a 
tropical year of 365^^ 5^^ 55' 13" 46'" had originally been known to the 
Siamese, and remarked that such a year differed by two seconds only 
only from Hipparchus’s year. We are now able to maintain that the two 
years originally did not differ at all, and that the later small divergence 
is merely due to the inaccurate proportion 
* 
which for reasons of 
convenience was preferred to the accurate one. 
We finally have to consider an interesting stanza in the 11th chapter 
of Brahmagupta’s Sphuta Siddhanta which contains some information 
about the sources from which the elements of the Bomaka Siddhanta 
were derived. The two manuscripts of the Sphuta Siddhanta at my 
disposal are unfortunately so incorrect that only a part of the stanza is 
intelligible; wdiat interests us more particularly can, however, be made 
out I think. One manuscript (containing the text of the Sphuta Sid¬ 
dhanta only) reads: 
