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faulty manner, and confequently any future aftrono- 
mers being deceived in their obfervations. 
There dill remained one objedt worthy of atten- 
tion, which 1 had alio propofed to the Royal Society, 
and received their encouragement to proceed in it. 
This was the obfervation of the horary parallaxes of 
the moon, by the difference of right afcenfion in 
time between the moon’s enlightened limb, and ftars 
near her parallel of declination : a kind of obferva- 
tion never before made to my knowledge, by any 
adronomer, in a latitude fo near to the equator, as 
St. Helena, which, by determining the mean hori- 
zontal parallax in that latitude, infers al fo, by a pro- 
portion, which will come out lenfibly the fame upon 
any probable hypothefis of the figure of the earth, 
the mean equatorial parallax, which hath never yet 
been deduced in any manner fo nearly diredt. 
For the purpofe of making thefe obfervations, I 
was provided with a polar axis, fuitable to the la- 
titude of the place, on which my reflecting telefc pe 
was mounted, and a particular additional eye-piece, 
having fine lilver wires lfretched in the focus of 
the neared eye-glafs. The cell containing the 
wires being moveable round about, by means of 
a fcrew, it was eafy to caule any ftar near the moon’s 
parallel of declination to run exadtly along one of 
the wires, which may be called the directing wire, 
from the centre to the extremity of the field of the 
telefcope. The exact infiants of the ftars pafling 
three wires placed perpendicular to the former, which 
may be called the horary wires, reprefenting fmall 
portions of horary circles, were noted by the clock 
Vol. LIV. Z z to 
