[ 6i 9 ] 
interval of the conta&s, and that the Ieafh diflance 
of the centers of the Sun and Venus, as feen from 
the center of the earth, is alio known. 
The method I have followed, in this enquiry, was 
by finding the total duration at the center of the 
earth : in order to find this, it was neceffary to know 
the leaf!; diflance of the centers of the Sun and Ve- 
nus as feen from the center of the earth. By the mea- 
furements of the diflance of the limb of Venus from 
the Sun’s limb taken at Savile-Houfe, and alfo by 
the like meafurements taken by Mr. Haydon at 
Lefkeard, I found, on the above fuppofition of the 
Sun’s parallax, that the leafl diflance of the centers, 
as feen from the center of the earth, was = 9' 32" . 
The total duration, therefore, at the center of the 
earth was 5 11 58'' 1 ". I have compared the feveral 
obfervations of the total duration with this central 
duration, and from each I have determined the Sun’s 
parallax, as may be feen more fully in the following 
table. I have inferted in this table the alteration of 
duration by one fecond of the Sun’s parallax at each 
place, by which may be feen the quantity of error 
in the determination of the Sun’s parallax arifing from 
any quantity of error in the obfervation. 
The times of the total duration at thofe different 
places 1 have taken from the Phil. T ranfadtions ; only 
thofe of Calmar and Cajaneburg I have taken from 
the Sweedifh adts ; the internal contact at the ingrefs 
at Cajaneburgh, in thofe adts, is at 4 11 18' 5", where- 
as it fhould be at 4 h 19" 5", as may be eafily proved, 
this being an error in writing down the minutes, 
which has happened more than once in thefe obferva- 
tions, occafioned by the hurry of writing down the 
times of the obfervations. The obfervations in the 
Eaft 
