C *54 ] 
The clouds greatly obftruCted Mr. Madeline's 
oblervations ; he could make but one that was ufe- 
ful. At y h 3i / o7 // in the morning, apparent time, 
the bodies both of the Sun and of Venus being per- 
fectly well defined, the diftance of the neared limbs 
was, by means of an objeCt-glafs Micrometer adapted 
to a reflecting telefcope according to Mr. Dollond’s 
invention, found to be I have computed 
that by allowing io" for the horizontal parallax of 
the Sun, from that phalis to the internal contaCt of 
the limbs, there muft have pafied 34' 52" at St. 
f Ielena ; I have even allured myfelf, by fome other 
calculations, that, by an alteration of one or two fe- 
conds in the parallax, and of feveral minutes of time 
in the longitude of St. Helena, the interval which 1 
have juft now determined would fuffer an increafe or 
diminution but of very few feconds. The internal 
contaCt of the limbs muft therefore have happened 
at St. Helena at 8 h o5 / 59 // in the morning. One 
can’t fuppofe it to have happened later, becaufe 17' 
after, or at about 8 h 2 3', the Ikies having cleared again, 
nothing more could be feen, and the external contact 
was over. This obfervation being compared with 
that of Tobollk, would give 1 l'Tor the horizontal par- 
allax, which is a little too much. Mr. Mafkeline 
obferves, that tho’ Venus’s limb and the Sun’s appeared 
as defined as could be defired, yet when the artificial 
internal contact of Venus’s limb with the Sun’s was 
made by means of the object-glafs micrometer, Ve- 
nus’s limb dilated and contracted itfelf alternately, 
getting and lofing a fmall fpace within the Sun’s limb. 
He adds, that he endeavoured to take it in the middle 
of this vibration, but dares not affirm that he ex- 
