VOL. LXXVII.3 PHILOSOPHICAL TRANSACTIONS. 225 



The apparent zenith distance of the pole, by the mean of 310 observations, is 



O / // 



38 30 36 allowing — 2" for the error of the line of collimation. 

 Refraction + 45 J 



38 31 21 J Co-lat. 38 31 21 i by the new quadrant. 



Latitude 51 28 38| 38 31 18| by the old quad, new divisions. 



apparent Zenith distances of the Pole observed with the Iron Quadrant. 



Thermometer. 



1753. 



\ 



Sept. 13 

 23 



Oct. 2 



5 



11 



19 



31 

 5 

 16 

 19 

 20 

 24 

 29 

 3 

 8 

 17 

 30 



Apparent zenith 



distance of the 



pole. 



38 30 



Nov. 



Dec 



Mean 

 Refraction 

 Col. 

 Pol. corr. 



40.1 



41.5 



42.5 



41.0 



41.1 



40.2 



40.8 



42.1 



40.5 



42.2 



40.9 



40.0 



40.0 



39.3 



37.4 



41.5 



38.0 



Barom. 



38 



38 



30 



+ 



40.5 

 46.4 

 — 8.4 

 31 18.5 



Inches. 

 30.10 

 29-88 

 29.67 

 30.02 

 29.48 

 29.82 

 29.65 

 29.69 

 29.39 

 29.59 

 29.84 

 30.00 

 29-80 

 30.16 

 30.06 

 29.50 

 30.11 



29. 81 



64 



61 



56 



57 



61 



50 



42 



45 



42 



40 



40 



43 



38 



39 



35 



50 



33 



out. 



47 



65 

 60 

 53 

 57 

 57 

 43 

 34 

 39 

 35 

 35 

 33 

 35 

 30 

 33 

 27 

 49 

 22 



4U 



So far the manuscript. 



Thus the latitude by the brass quadrant being 51° 28' 88y, and by the iron 

 quadrant with new divisions 51° 28' 4 1^'''', the mean by both quadrants is 5 1*' 

 28' 40", or only half a second greater than settled in another manner, according 

 to the manuscript of Dr. Bradley in my possession. Also the apparent zenith 

 distance of the pole with the mean refraction 45''.4 being 38° 30' SS'^l by the 

 brass quadrant, and 38^ 30' 33^.1, by the iron quadrant, the mean by both is 

 38° 30' 34'''.6, or only TV^hs of a second less than by Dx. Bradley's manuscript 

 cited before. > 



On my promotion to the Royal Observatory in 17^5, finding its latitude to 

 have been so accurately settled by Dr. Bradley before me, I might have thought 

 myself dispensed from making any particular or very laborious observations for 

 that purpose; however, I confirmed it by my own observations to great nearness, 

 viz. within 1 or 2", at the same time that I was establishing a new catalogue of 

 the principal fixed stars, continually observed here for settling the right ascensions 



VOL. XVI. G G 



