Bīrūnī, Muḥammad ibn Aḥmad, Alberuni's India (v. 2)

(London :  Kegan Paul, Trench, Trübner & Co.,  1910.)

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58
 

ALBERUNTS INDIA.
 

Method of
Pulisa for
the same
purpose.
 

Explana¬
tory notes
thereon.
 

This kind of computation may be continued if we
want to have seconds and minor values. The quotient
represents the place of that planet according to its
mean motion, or the place of that apsis or that node
which we wanted to find.

The same is also mentioned by Pulisa, but his
method differs, as follows:—" After having found
the com]3lete cycles which have elapsed at a cer¬
tain moment of time, he divides the remainder by
131,493,150. The quotient represents the mean signs
of the ecliptic.

"The remainder is divided by 4,383,105. The quo¬
tient represents degrees. The fourfold of the remainder
is divided by 292,207. The quotient represents minutes.
The remainder is multiplied by 60 and the product
divided by the last-mentioned divisor. The quotient
represents seconds.

" This calculation may be continued, so as to give
third parts, fourth parts, and minor values. The quo¬
tient thus found is the mean place of the planet which
we want to find."

The fact is that Pulisa was obliged to multiply the
remainder of the cycles by 12, and to divide the pro-^
duct by the days of a cctturyugct, because his whole
computation is based on the cctturyuga. But instead
of doing this, he divided by the quotient which you
get if you divide the number of days of a caturyuga by
12. This quotient is the first number he mentions, viz.
131,493,150.

Further, he was obliged to multiply the remainder
of the signs of the ecliptic by 30, and to divide the
product by the first divisor; but instead of doing this,
he divided by the quotient which you get if you divide
the first number by 30. This quotient is the second
number, viz. 4,383,105.

According to the same analogy, he wanted to divide
the remainder of the degrees  by the quotient which
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