The Astronomical Observatories of Jai Singh c9.s1.34

c9.s1.34

35. Of these instruments it is claimed that Jai Singh devised the Samrāṭ Yantra, Jai Prakāś and Rām Yantra. The evolution of these instruments will be dealt with in a concluding chapter, but it may be remarked here that Jai Singh's ingenuity was chiefly concerned with the transference of designs, previously executed in instruments of comparatively small size, to huge masonry instruments. No new invention, in the ordinary sense of the word, was attempted. The Samrāṭ Yantra is, in principle, a very simple form of sun-dial, but it is an efficient instrument, and, as Jai Singh designed it, a dignified structure. There is, so far, no evidence to show that the tangent scales on the edge of the gnomon had been previously used as on the Samrāṭ Yantra; therefore, besides the general design, we may credit Jai Singh with this device. The Jai Prakāś or ‘invention of Jai,’ as it may be called, and which Jagannāth calls the ‘crest jewel,’ is really a sort of combined armillary sphere. Possibly the astrolabe projections suggested the idea to Jai Singh. In a manuscript copy of a work by Abdul Ali Barjendi¹ (died A.D. 1523) most of the details of such an instrument as the Jai Prakāś are given. Jai Singh's duplicated instrument is, however, his own design, and, probably, the introduction of the culminating sign lines must be attributed entirely to his own invention.