i6o Dr. Maskelyne’s Obfervations on the Latitude 
“ Auguft 12, 1753, I meafured with the fcrew of my mi- 
“ crometer the difference of the arcs (of .£♦) as fet off by 
“ Mr. Graham originally, and by Mr. Bird when he put 
<£ on a new fet of divisions upon the old quadrant, and I 
“ found that Mr. Graham’s arc was lefs than Mr. Bird’s by 
ee T %. divifions of my micrometer, which to a radius of 96 inches 
66 anfvvers to 10", 6 ; fo that the whole arc of 96 differs from 
“ a true quadrant 15", 9, which is the fame difference that I 
“ formerly foilnd by means of the level, &c.” 
Let me further add, that Dr. Bradley had informed me, 
that he had found the fame refractions, latitude of the Obfer- 
vatory, and obliquity of the ecliptic, by both quadrants, 
making a proportionable allowance, in the ufe of the iron qua- 
drant, for the error of 16" in the total arc in proportion to 
the zenith diftance of the objeCt before it was new divided. 
The Rev. Dr. Hornsby, F. R. S. Savilian Profeffor of 
Aflronomy at Oxford, to whofe care Dr. Bradley’s original 
obfervations have been committed, in order to their being 
printed and publifhed, having favoured me with calculations of 
the latitude of the Royal Obfervatory from obfervations of the 
pole ifar made with both quadrants, from a manufcript of Dr. 
Bradley, I think it proper to give it a place here, not only as 
a very curious paper, but alfo as ftrongly confirming the lati- 
tude of this place before Rated. 
Tranfcribed from a Joofe Paper oj Dr. Bradley. 
“ The mean zenith diftances of the pole flar above and below 
ci the pole, corre&ed by refraCtion, aberration, &c. and re- 
“ duced to January 1751, O. St. as collected from the obfer- 
“ vations made after the new quadrant was balanced, Nov. 
“24, 1750. 
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