f 
172 Dr . Maskelyne’s Obfervations on the Latitude 
obfervations, exceeds 48° 5F 4" the mean of the obfervations of 
Meff. Maraldi, le Monnier, and Cassini deThury, by 8 V , 
and at the fame time his refractions for that altitude exceed what 
they adopt by the fame quantity. 2. His refractions are greater 
than all other tables give, Dominico Cassini’s, Flamsteed’s, 
Newton’s, Bradley’s, Mayer’s, Simpson’s, and Lord Mac- 
clesfield’s. The latter I have by me in a manufcript of Dr. 
Bradley, being what he ufed to correCt his obfervations by, be- 
fore he had been enabled to determine the refraCtions with the 
new mural arc. They were deduced from a brafs quadrant of 
5-feet radius made by Mr. Sisson, ftill remaining in the Obferva- 
tory at Sherburn -Cattle, and are the more to be efteemed becaufe 
the divisions of the inftrument had been fubmitted to the friftejl 
re-examination , whereby, in the opinion of Dr. Bradley, it was 
probably rendered as p erf eft in its kind as any extant , or as human 
Jkill could at that time produce. See Dr. Bradley’s Letter to Lord 
Macclesfield, Phil. Tranf. vol. XLV. p. 5. The refraCtions in 
this table are lefs than Dr. Bradley’s by 2", 4 at the altitude of 
4 5 0 , and 4" at the altitude of 20°. Mayer’s refraCtions agree almoft 
exaCtly with Dr. Bradley’s, and are entitled to much weight, 
having been determined by a 6-feet mural arc conftruCted by Mr. 
Bird. 5. The refraCtions were found by the French Academicians 
at the polar circle, according to M. Maupertuis’s Book on 
the Figure of the Earth, to agree nearly with Dominico Cas- 
sini’s table. Hence it may be inferred, that the refraCtions in 
a warmer climate, as France, Ihould be lefs than according to 
the fame table, and therefore much lefs than according 
to M. de la Caille’s, and approaching to Dr. Brad- 
ley’s, which are a little lefs than M. Cassini’s. 4. M. le 
Monnier, after his return from the polar circle, with a qua- 
drant examined at the zenith and horizon, and after making 
allowance for the error thereby inferred in the total arc, ob- 
2 ferved 
