ब्राह्मस्फुटसिद्धान्त (ब्रह्मगुप्त - शून्य, कुट्टक, बीजगणित एवं सम्पूर्ण २१ अध्याय सान्वय सटीक)

ALGEBRA GOES TO EUROPE FROM INDIA 193
628. The grounds on which they proceeded are unfor-
tunately not specified : but as they gave Bhāskara's
age correctly, as well as several other dates right,
which admit of being verified; it is presumed that they
had grounds, though unexplained, for the information
which they communicated..
Mr. Bentley, who is little disposed to favour the anti-
quity of an Indian astronomer, has given his reasons
for considering the astronomical system which Brah-
magupta teaches, to be between twelve and thirteen
hundred years old (1263 years in A.D. 1799). Now as
the system taught by this author is professedly one
corrected and adapted by him to conform with the
observed positions of the celestial objects when he
wrote, the age, when their positions would be conform-
able with the results of computations made as by him
directed, is precisely the age of the author himself :
and so far as Mr. Bentley's calculations may be consi-
dered to approximate the truth, the date of Brahma-
gupta's performance is determined with like approach .
to exactness, within a certain latitude however of
uncertainty for allowance to be made on account
of the inaccuracy of Hindu observations.
The translator has assigned on former occasions the
grounds upon which he sees reason to place the author's
age, soon after the period when the vernal equinox
coincided with the beginning of the lunar mansion and
zodiacal asterism Aśvini, where the Hindu ecliptic
now commences. He is supported in it by the senti-
ments of Bhāskara and other Indian astronomers, who
infer from Brahmagupta's doctrine concerning the
solistitial points, of which he does not admit a periodi-
cal motion, that he lived when the equinoxes did not,
sensibly to him, deviate from the beginning of Aśvini
and middle of citrā on the Hindu sphere. On these
grounds it is maintained, that Brahmagupta is rightly
placed in the sixth or beginning of the seventh century
of the Christian era, as the subjoined calculations will
more particularly show. The age when Brahmagupta