j 54 Dr. Maskelyne’s Ob/irvations on the Latitude 
queftion, and obviate the principal difficulty, that relative to 
the difference of latitude of Greenwich and Paris, and reduce the 
difference of meridians within fmaller limits, notwithftanding 
Dr. Bradley’s original obfervations had been removed from 
this Obfervatory, in which they were made, before I came 
here, and have not yet been reftored to it. 
Dr. Bradley having been furniffied by Government in the 
year 1750 with a brafs mural quadrant of eight feet radius, 
conffrudted by that excellent artift Mr. John Bird, an inffru- 
ment far fuperior to any before ufed in the pradtice of aftro'- 
nomy, affiduoufly obferved the pole ffar and other Bars lying 
to the north of the zenith with it for upwards of three years, 
and then removed it to the oppofite fde of the wall, making it 
change place with the iron quadrant of the fame radius 
conffrudted by Mr. Graham, likewife an excellent inftru- 
ment, though inferior to this, and commenced a regular 
feries of obfervations of the fun, planets, and fixed Bars, 
which have been ever fince continued in the fame manner. 
Moreover, the temperature of the air, ffiewn by the barome- 
ter and thermometer, is affixed to each obfervation ; and the 
zenith point of the quadrant fettled from time to time by the 
help of a zenith fedlor of 12I feet radius, turned alternately 
contrary ways, the fame with which Dr. Bradley had before 
made his two ufeful and admirable difcoveries of the aberration 
of light and the nutation of the earth’s axis. 
By the obfervations of the pole ffar and other circum- 
polar Bars, above and below the pole, Dr. Bradley got the 
apparent zenith diftance of the pole ; by the apparent and 
equal zenith diffances of the fun at the two equinoxes, having 
at the fame time oppofite right afcenfions, as found from com- 
paring his obferved tranfits over the meridian with thofe of 
5 hxed 
