"Bradley's first object after his removal to Greenwich was to repair the instruments, and carefully to adjust their positions. Halley had confined himself to the use of the mural quadrant soon after its erection in 1725. Bradley, however, resolved to employ both the quadrant and the transit instrument in his observations. The former of these instruments was repaired by Graham, and the latter by Sisson, several important improvements being at the same time effected in their construction. Bradley's first observation with the quadrant was made on the 15th of June, 1742. His earliest transit observation is dated the 20th of July in the same year."