Royal 
October. 
Society. 
April. 
13 
Minut. 
Semi- 
Mmut. 
Semi- 
Dift. 
dura t. 
Dift. 
durat. 
' 
h. m. 
I 
h. m. 

2 44 

4 oi 
I 
2 44 
I 
4 
2 
2 43 
2 
3 58i 
3 
2 41} 
3 
3 5^ 
4 
^ 35>i 
4 
5 53 
5 
2 5^T 
^ 5 
; 48I 
6 
^,i. 
d32 
6 
3 43 
7 
2 281 
7 
5 3^' 
8 
2 23 
8 
3 28 
9 
2 17 
9 
3 i8f 
10 
2 10 
10 
3 7 
II 
2 I 
II 
2 44 
12 
I 51 
'- 
2 58 
13 
I 39 
13 
2 19 
14 
I 24 
H 
I 55 
15 
I 4 
15 
I 21I 
Mi 
16 
50 
30 
I5i 1 
5'^ 
Thefe numbers do fitly reprefent all the obfervatlons hitherto 
made, nor need we doubt of the future 5 feeing of all the planets 
Mercury is the neareil to the fan, fo that it cannot in the leaft be 
intercepted by the intervention of the centres of the other planets, 
nor fenfibly difturbed by thole deviations, which a rile from their 
fyflems, and to which the fuperior planets, particularly Saturn^ 
are obnoxious: Mr. Halley deiignedly omitted the parallaxes as 
very inconliderable, and which being different, in different places, 
could not be applied in a more general calculation, and becaufe 
their quantity hath not hitherto been determinedi but from fuch 
obfervations they may rather be more certainly derived ^ he had 
alio as little a regard to Mercury ^ diameter, becauie, being ex- 
tremely Imall, he leems to adhere for a very few minutes to the 
limb ^ for by an accurate obfervation, OEiober 28, 1^77, he found, 
that fcarcelytwo minutes were elapfed, when he entirely quitted 
theflin^ whcnce-^e concluded its diameter to be o' u'^ and 
according to the ratio of the diftances fl-om the earth at the other 
node, o' 13'/ \ nearly; therefore 3 I minutes are fpent, while 
the whole planet direflly pervades the fun's limb; but paffing ob- 
liquely, he continues thereon a little longer, in the ratio of the 
in- 
