[ 161 3 
which I compared with the clock, and found it had 
not altered in the leaft. 
From my fir ft perceiving the change of the figure, 
to the intire ingrefs, could not be a full minute. 
By a flight calculus I had made, the occultation 
was not to laft half an hour? but the ingrefs con- 
fiderably anticipating it, I conjectured, that, on the 
contrary, the egrefs would be later, as it proved to 
be. 
I muft here take notice, that not the leaft glimpfe 
of the moon, then not two days old, could be - dis- 
cerned : fo that the bufinefs of fecuring Venus, at 
the inftant of her emerfion, within the field of the 
telefcope, over which fhe pafled in about 2 1 1 o", de- 
pended intirely on a due management of the fcrew, 
which gave motion both to the equatorial or horary 
plate, and to the telefcope. A little after 1 1 I brought 
the point of the hour-circle, anfwering to Venus, to 
the index, and might then have feen her near the 
middle of the field, had fhe already emerged Every 
two minutes after I was careful to turn the fcrew fo 
much, as to be fure of keeping her within the field. 
At length clapping my eye to the inftrument imme- 
diately after one of thefe operations, I perceived her 
quite emerged and round : this was at n b 13' 15" by 
the watch, which ftill kept exadt pace with the 
CiOck. 
I cannot think my eye had been removed more 
than a minute : my Lord Duke judged not quite fo 
much. 
Mr. Short had the misfortune not to recover fight of 
Venus till about a minute later than I did, for want 
of an affiftant, who knew how to govern the fcrew. 
X Venus 
