TRUB DAILY MOTION OF MARS, ETC. mandakendra of the twice-corrected planet) to or subtract that from the (planet's) mean daily motion (according to the law of addition and subtraction in the four quadrants). Set down the result at two places. At one place (subtract that from the daily motion of the sighrocca and then) calculate (the arc corresponding to) the sighrakendrajyagatiphala. Add the entire of that (arc) to or subtract that from the result kept at the other place (according to the law of addition and subtraction in the four quadrants). Thus is obtained the desired true daily motion (of the planet). 149 When the result derived from the sighra operation (i.e., the arc corresponding to the sighrakendrajyagatiphala) cannot be subtracted from that, the difference between the two then denotes the value of the true daily motion and the planet is said by the learned to be retrograde.³ This is the method for finding the true daily motion in the case of Jupiter, Saturn, and Mars. Now is being des-. cribed the method for Venus and Mercury. Increase or diminish (as usual) the mean daily motion of Venus or Mercury by the entire motion-correction (i. e., manda- kendrajyagatiphala) determined from the corrected mandakendra and also by that obtained by proceeding according to the rule 1 The process is: Multiply the difference obtained after subtraction from the daily motion of the sighrocca by the current Rsine-difference corresponding to the sighrakendra and also by the corrected sighra epicy- cle and divide that product by 18000: the result is the sighrakendra- jyagatiphala. Multiply that by the radius and divide by the sighrakarna, and reduce that to the corresponding arc.
- That is, the result kept at the other place.
3 This rule is found also in SiDV, I, ii. 38-40.
