14 M E M O I R S o;^ /;6<? 
increafe of the fecants of the angles of incidence : There is alfa 
as little occaiion to eftimate the equations of time, becaufe for 
many days in each month they continue conllant, and, as it were, 
invariable. 
Of the vifible conjunction of Venus with the fun : This fight, 
which is by far the nobleft that aflronomy affords, like the fecular 
games, is denied mortals for a whole century by the flridt laws of 
motion 3 it will be afterwards fhewn, that by this obfervation 
alone, the diftance of the fun, from the earth, might be deter- 
mined with the greatefc certainty', which, on account of the pa- 
rallax orherwife entirely infenfible, hath not hitherto been pre- 
cilely defined: As to the periods, they cannot be 16 accurately 
determined as thofe o^ Mercury\ feeing Venus has only once, fince 
the creation, been obferved withm the fun's difk, and that by our 
countryman Horrox: After having corrected the motions, as 
much as the ruder oblervations of the ancients would permit, the 
lum of the calculation is as follows, 
S o ' y 
The longitude of the alcending node of Venus y"? . 
from the firilftar of Jries -^ — — 5 ' ^5 i^ CO 
Therefore the fun is in conjunction with her in ) 
the oppofite point, that is, in thefe centuries,^ 7 15 i(5 00 
about the end of 'November — — — ^ 
The diftance oi Venus from the fun 71997 parts. 
— ; — ; — ^ the earth 2^458. 
The inclination of Venus^ orbit to the ecliptic o 513 o 
The motion of Venus in eight fidereal years,? ^^01 
over 15 revolutions — — . — — — 5 130202 
The motion of Venus in 235 fidereal years,? 
over 38 revolutions — ■ — — — • — 3 ^^^7 39 
The motion of Venus in 243 fidereal years,? ^ ^ 
over 395 revolutions — — — — — 3 '^ ^^ 
From thele elements making a Calculus according to the 
method explained in Mercury^ the intervals of the times and 
diilances arife as follows : After 8 years Venus revolves to the 
fun 5 viz. after fubftraCting from the moment of the former tranfit 
2d. 10 h. 52 Y m. and the planet proceeds in a path 24' 41^' 
more Ibuthcrly than the preceeding : After 235 years, having 
added 2 d. 10 h. 9 m. Venus may again enter the fun, but 11' 
33/{>more northerly ^ but if the preceeding year be biffextile, 
3d. 10 h. 9 m. are to be added: After 243 years, Venus may 
likewifc pais over the fun, fubftraCting only o h. 43 m. from the 
time of the former 3 but it advances 13' 8'^ more foutherlv 5 but if 
the 
