2l6 PHILOSOPHICAL TRANSACTIONS. [aNNO 177". 



shadow of a gnomon on two quadrants, one situated to the east, and the other 

 to the west of it; and indeed the chief part of their instruments at this place 

 appear to be constructed for the same purpose, except tiie quadrants, and a brass 

 instrument described hereafter. Figure b is another instrument for the purpose 

 of determining the exact hour of the day by the shadow of a gnomon, which 

 stands perpendicular to and in the centre of a fiat circular stone, supported in an 

 oblique situation by means of 4 upright stones and a cross piece; so that the 

 shadow of the gnomon, which is a perpendicular iron rod, is thrown on the 

 divisions of the circle described on the face of the flat circular stone. Figure c 

 is a brass circle, about 2 feet diameter, moving vertically on 2 pivots between 2 

 stone [pillars, having an index or hand turning round horizontally on the centre 

 of this circle. This instrument appears to be made for taking the angle of a 

 star at setting or rising, or for taking the azimuth or amplitude of the sun at 

 rising or setting. 



The use of the instrument, figure d, I was at a loss to guess. It consists of 

 2 circular walls; the outer of which is about 40 feet diameter, and 8 feet high; 

 the wall within about half that height, and appears intended for a place to stand 

 on to observe the divisions on the upper circle of the outer wall, rather than for 

 any other purpose; and yet both circles are divided into 36o degrees, each 

 degree being subdivided into 20 small divisions, the same as the quadrants. 

 There is a door-way to pass into the inner circle, and a pillar in the centre, of 

 the same height with the lower circle, having a hole in it, being the centre of 

 both circles, and seems to be a socket for an iron rod to be placed perpendicu- 

 larly in it. The divisions on these, as well as all the other instruments, will 

 bear a nice examination with a pair of compasses. Figure e is a smaller equi- 

 noctial sun-dial, constructed on the same principle as the large one a. 



This observatory at Benares is said to have been built by the order of the 

 emperor Ackbar; fo'' as this wise prince endeavoured to improve the arts, so he 

 wished also to recover the sciences of Hindostan, and therefore directed that 3 

 such places should be erected: one at Delhi, another at Agra, and the 3d at 

 Benares. Some doubts have arisen with regard to the certainty of the ancient 

 Bramins having a knowledge in astronomy, and whether the Persians might not 

 have introduced it into Hindostan when conquered by that people: but these 

 doubts I think must vanish, when we know that the present Bramins pronounce, 

 from the records and tables which have been handed to them by their forefathers, 

 the aiiproach of the eclipses of the sun and moon, and regularly as they advance 

 give timely information to the emperor and the princes in whose dominion they 

 reside. There are yet some remains in evidence of their being at one time in 

 possession of this science. The signs of the zodiac, in some of their choultrys 

 on the coast of Coromandel, as remarkefl by John Call, Esq., f. u. s., in liis 



