INTRODUCTION xxxvili th question : Now, only seven planets are to be seen revolving in the sky. And, their revolutions have already been enumerated. What are these (new bodies), the nodes and apogees, whose revolutions are being enumerated here ?' Then he provides the reply : '(The answer) is stated thus : These (nodes and apogees) are (not material objects but) just some special numerical figures which have been conceived (by astronomers) as a means to compute the true motion etc. of the selfsame planets (mentioned earlier). These do not have any visual appearance in the sky.” (p. 17). 14. Use of 'Siya', a unique measure denomination Under Gaņita 26, Suryadeva sets the following example : “(A certain commodity measuring) one and one-eighth of a siva is bought for 12 panas ; how much of the same (commodity) could be bought for 6 panas ၇•• The solution given by him shows that the Siva mentioned in the above example is a measure of weight, equivalent to 8 prasthas. In Indian mathematical parlance the word Siva is used to denote the number 11, in conformity with the number of the rudra-s (siva), being eleven, but we have so far not come across this term used to indicate a measure of weight. But use of this measure by Suryadeva shows that this measure was in use in the locality where Suryadeva lived. 15. Lord of the civil year Aryabhata gives a method to find the lords of the hour and the day (Kala., 16), but he does not say how the lord of the civil year or the civil month is to be found. Suryadeva, however, gives the following method in this regard : "Subtract 13, 17,416 from the civil days elapsed since the beginning of Kaliyuga. The remainder divided by 360 gives the civil years —ത്തി =n= 1. Cf. : ननु सप्तैव ग्रहा। व्योम्नि भ्रमन्तो दृश्यन्ते । तेषां च भगणा पूर्वमेवोपदिष्टाः । क एते उच्चपाता येषामत्र भगणोपदेशः क्रियते ? उच्यते---तेषामेव ग्रहाणां स्फुटगत्यादिपरिज्ञानोपायभूताः केचन संख्याविशेषाः । नैषां व्योम्नि दर्शनमस्ति ॥ (Com. on i. 4, p. 17).
