[ *74 ] 
be made to that inftrument, which could not be 
completed before Tuefday evening, the id inftant, 
and which we received at the Obfervatory, early the 
following morning. But as it is abfolutely neceftary, 
that the telefcope fhould be nicely adjufted to di- 
ftinCt vifion, for the obferver’s eye, otherwife the 
apparent angle, meafured by the micrometer, will 
not be exactly true ; and as the eyes of different ob- 
fervers may vary very much; the weather was fo very 
unfavourable, that I had not fo much as one oppor- 
tunity of feeing any celeftial object, whereby I might 
ft it to the proper focus of parallel rays for my eye. 
Mr. Green therefore, Dr. Bradley’s affiftant, was the 
only perfon who could ufe that inftrument, having 
adjuffed it to his eye fome time before. The inftru- 
ment I made ufe of myfelf, was an exquifite mi- 
crometer, of the old form, made by the late Mr. 
Graham, adapted to an excellent refracting telefcope 
of i y feet focal length. The fky was fo very cloudy 
the morning of the tranfit, and the apparent proba- 
bility of its clearing up fo very fmall, that we almoft 
defpaired of being able to make any obfervation ; for 
we had but one glimple of the fun, and that only 
for about half a minute, till half an hour after feven 
o’clock. We then prepared to obferve the diftance 
of Venus from each limb of the fun, on the chords 
parallel to the equator, by Mr. Green, with the re- 
deCting telefcope, and its micrometer ; and I myfelf, 
with the refracting telefcope, and the old micrometer, 
obferved differences of right afcenfion and declination 
from the confequent and fouthermoft limb of the 
dan. 
The 
