xxxiv ÄRYABHATIYA the shpere rotates one half. Similarly, in the next 30 ghatikas the entire water flows out, the gourd reaches the bottom of the cylinder and the sphere completes one full rotation. In this manner, the sphere could be rotated intelligently keeping pace with time.' (Gola, 22, pp. 143-44). 7. Verification of a Computational System Explaining the method of the verification of astronomical computation by observation Suryadeva states : “In an open spot construct a perfectly circular platform of desired radius in angulas, raised to the height of the eye, with the east-west and north-south lines drawn (through the centre) and 21,600 equal divisions (of minutes) marked on its circumference. Then, at sunrise and sunset, stand (in turn) at the west and east sides of the platform and observe the half-risen and half-set Sun, respectively, and mark their positions on the circumference as indicated by the gnomon (fixed at the centre of the circle). Mark also the opposite points on the circumference as indicated by the shadow of the gnomon. Mark also a point at the tip of the mid-day shadow. When the Sun is in the northern hemisphere, place another gnomon on the east-west line and observe daily the entrance of the shadow on that line. These observations should be continued for two or three years. If the sun, observed thus, is seen exactly in the positions arrived at by computation, then that computation is to be understood as correct. If the time of the entrance of the midday shadow on the north-south line corresponds to that derived by computation, then also the correctness of the computation is verified. In the same way, the correctness of the computation may be verified also by the observation of the north-south midday shadow, when it is either maximum or totally absent. The verification of the computed Sun with the observed Sun is done in this manner. "The Moon will also be correct if the computed conjunction of the Moon with the observed Sun is found to be identical with the observed one at the time of eclipses. And, the other planets too will be correct if the computed conjunctions of the Moon (as verified) above with the computed planets are in conformity with the observed one, to be correct.” (Com. on Gola, 48, pp. 182-83). 8. A discrepancy in Lalla explained After specifying that at Kali 3600 (Šaka 421), when the Arya
