832 Description of an Astronomical Instrument. [Oct. 



astronomy is fading away in its native soil, — a decay which the 

 Brahmins themselves readily admit; and which they attribute to the 

 little encouragement held out to those who profess it. Although the 

 relaxation of the grasp in which the Brahmins have long held the 

 Indian mind, can be no subject of regret, and the discredit of their 

 vaticinations no ground for lament ; yet those who delight to trace the 

 history of the human mind, and who contemplate with satisfaction 

 the monuments of its industry and power, must ardently desire 

 that Indian astronomy should be embalmed, as entire and perfect 

 as possible, in scientific history. To effect this, the lover of science 

 should allow no fact to escape him, being assured, that so soon as the 

 sciences of the West have been diffused over India, so soon will 

 Indian astronomy be but a name. 



I shall begin my particular description of the instrument by 

 showing its use in finding the time of the civil, or bhumi sdvan, day, 

 which with the Indian extends from sunrise till sunset. For this pur- 

 pose the inner quadrantal arc, described upon the obverse of the instru- 

 ment, is graduated from right to left to fifteen prime divisions, these 

 again being subdivided into six equal parts ; the former being the num- 

 ber of dundas in half the Indian equinoctial day, and the latter being 

 arcs of ten pulahs each, equal to four of our minutes. This will be 

 rendered more plain by the following table of Indian divisions of time. 

 6 Respirations = 1 Vicala. 

 60 Vicala = 1 Dunda. 



60 Dundas = 1 Nachshatral day* 



In order to find the time of the day, the observer places the index 

 rod upon its axis, which is fixed near one extremity of the tube, and 

 raises the instrument in the vertical plane till he can see the 

 sun through the tube ; he now marks what part of the circle of time 

 just described is cut by the rod, and reads off the number of hours and 

 minutes, proximately, which the sun has of altitude, and this being 

 added to the time of sunrise, or subtracted from that of sunset, (data 

 which their almanacks supply) gives him the hour of the day. I need 

 scarcely mention, that though the result is not strictly true even with- 

 in the tropics, yet it is sufficiently so for the Indian astronomer, who 

 diminishes its errors by compensations, a mode of correction to which he 

 is accustomed, and in the application of which he is exceedingly skilful. 

 The outer circle is an arc of the meridian intercepted between the 

 equator and the pole, and is graduated to 90°, the divisions being num- 



* Nachshatral day, the time of an entire revolution of the earth, 



