OP THE ECLIPTIC. 195 



9. The successive observations were taken as is usual, with the limb 

 of the circle facing alternately east and west, and latterly care was taken, 

 that previous to letting the light in, it should be equally heated , which 

 was done by inverting it from the position it was in during the morning, 

 a short time before the sun's passage over the meridian. 



10. Immediately before observing I set the micrometers at zero, the 

 horizontal wire being on the mark, and immediately after taking the al- 

 titude I renewed the operation. Between these two readings there seldom 

 was a difference above 2. The mean was always registered, 



11. The instrument is placed on the center granite pillar in the ob- 

 servatory, and is in every respect perfectly fixt and steady. The tem- 

 perature was always noticed at the time of observation, with a view to the 

 refraction, which was computed (without reference to the tables ) from 

 Bradley's Formula, and with the constant quantities given in my paper 

 on the declination of stars, published in the XI. vol. of the Asiatick re- 

 searches. The sun's declination used for the. reductions, and also for the 

 latitudes, was invariably interpolated for the exnct moment from the 

 tables given in the Ephemerides. The parallax was taken for the month, 

 and day, from Bradley's tables, given in Callet's Logarithms. 



12. The Brahmin assistant, Sanevasa-chairy", always observed the 

 transit of the sun, whilst I was taking its meridional altitude, which formed 

 also a powerful check, against any irregularity which might have creptin, 

 From the instrument being disturbed from the meridian, when I elevated 

 the telescope. How far these precautions have succeeded will best be 

 Ishewn by what follows. 



