The Astronomical Observatories of Jai Singh c14.5

c14.5

62. "At Matra," wrote Hunter in 1799,² "the remains of the observatory are in the fort, which was built by Jayasinha³ on the bank of the Jumna. The instruments are on the roof of one of the apartments. They are all imperfect, and, in general, of small dimensions. (1) An equinoctial dial, being a circle nine feet two inches in diameter, placed parallel to the plane of the equator and facing northwards. It is divided into degrees, which are numbered as pals 10, 20, 30, 40, 50, 60: lastly, each subdivision is further divided into five parts, being 12 minutes or two pals. In the centre is the remains of the iron style or pin, which served to cast the shadow.⁴ (2) On the top of this instrument is a short pillar, on the upper surface of which is an amplitude instrument, but it is only divided into octants. Its diameter is two feet two inches.⁵ (3) On the same level of the terrace is another amplitude instrument, divided into sixty equal parts. Its diameter is only thirteen inches. (4) On the same terrace is a circle, in the plane of the horizon, with a gnomon similar to that of a horizontal dial, but the divisions are equal, and of six degrees each. It must therefore have been intended for some other purpose than the common horizontal dial, unless we may conceive it to have been made by some person who was ignorant of the true principles of that instrument. This could not have been the case with Jaysinha and his astronomers; but the instrument has some appearance of being of a later date than most of the others: they are all of stone or brick, plaistered with lime, in which the lines and figures are cut; and the plaister of the instrument, though on a level with the terrace, and consequently more exposed to accidents than the others, is the freshest and most entire of them all. (5) On the east wall, but facing westward, is a segment, exceeding a semi-circle, with the arch downwards. It is divided into two parts, and each of these into fifteen divisions. Its diameter is four feet. On the west wall, facing eastwards, is a similar segment, with arch upwards divided into the same way as the former. Its diameter is seven feet nine inches.”