Royal Society. 5 
But from the arch 5^' 10'' and given angle, the per-p ^ \ // 
pendicular or nearcft diflance of Mercury from the^ o 8 3 
lun becomes — • — — — — J 
Therefore Mercury feen within the fun after 1 3 years 
advances more northerly by 8' 3'' 
go'// 
By the like realbning in ^6 fidereal years? u o 25 8 
Mercury moves — — • — S 
There are therefore wanting to 191 intire? ^ 
revolutions — — • — — S 
h. m. 
That is in time — - — — — 812 
By which the liin is advanced — — — .02041 
This arch feen from the earth becomes — — o 9 0^ 
The bafe anfwering thereto — — — 093^ 
h. m. 
The time, in which Mercury runs over the bale, is i 30 
But 4^ iidereal years exceed as many Julian with 11^^ 
intercalations by — -— — — 3 ^ 
And Mercury returns to the fun after 45 Julianl 
years and befides — ■ — — — 5 
Or, with 1 2 intercalations, that it becomes, when -o 
the preceeding year is either the fecond or third > o 4 51 
after Sijjet^tile _ >_ _™, — ^ 
But the perpendicular, by which Mercury advances? 
to the north, becomes — > — — S 
I 22, 
The moil accurate period of Mercury to the fun 7 
is abfolved in 2(53 fidereal years and befides _f 
And thefe Iidereal years exceed as m.any Jidianl 
with 66 intercalations by — ■ — - \ 
b. m, £ 
I II 30 
[Q 20 O 
-1. h. m, f 
Whence after 2*^3 Julian years Mercury re 
volves to the fun, but later by — 5° ^^ 33 5^ 
But if the preceeding year be ^/^xY/75', add i 11 31 30 
Ar length after this interval it advances more? 
northerly by _--, _ _ ^^^^^^^ 
The other wider periods are eaiily dilcovered from what has 
been juft new found, and they are either of 6 or 7 years 5 that of 
Vol. III. B 7 years 
years 
