224 



PHILOSOPHICAL TRANSACTIONS. 



[anno 1787. 



Let me further add, that Dr. Bradley had informed me, that he had found the 

 same refractions, and latitude of the Observatory, and obliquity of the ecliptic, 

 by both quadrants, making a proportionable allowance, in the use of the iron 

 quadrant, for the error of l6" in the total arc in proportion to the zenith distance 

 of the object before it was new divided. The Rev. Dr. Hornsby, f. r. s. Savilian 

 Professor of Astronomy at Oxford, to whose care Dr. Bradley's original observa- 

 tions have been committed, in order to their being printed and published, having 

 favoured me with calculations of the latitude of the Royal Observatory from ob- 

 servations of the pole star made with both quadrants, from a manuscript of Dr. 

 Bradley, I think it proper to give it a place here, not only as a very curious 

 paper, but also as strongly confirming the latitude of this place before stated. 



Transcribed from a loose Paper of Dr, Bradley. — " The mean zenith distances 

 of the pole star above and below the pole, corrected by refraction, aberration, &c. 

 and reduced to January 1751, o. s. as collected from the observations made after 

 the new quadrant was balanced, Nov. 24, 1750." 



Error of collimation 



T7 



38 



2 

 31 



47.48 



23.74 



1.74 



Co-Jatitude 38 31 22. 



to 



Jan, 15, 

 Aug. 27, 

 May 4, 

 Nov. 10, 

 May 31, 

 July 26, 



1751 

 1751 

 1752 

 1752 

 1753 

 1753 



