i6 
M E M O I R S g/- />6^ 
May. 
Year 
Time of Conjunct. 
Dift. from 
the Sun's Centre 
d. h. m. 
/ 
// 
IC48 
24 13 45 
5 
50 N. 
1283 
25 8 14 
5 
51 s 
1291 
25 15 9 
14 
27 N. 
1518 
25 i(^ 32 
14 
52 S. 
1526 
23 P 37 
5 
5 N. 
1751 
25 17 55 
4 
15 S. 
1169 
25 II 00 
15 
43 N. 
1996 
28 2 13 
13 
5^ x; 
2004 
25 19 18 
^ 
22 N. 
As to the duration of thefe eclipfes of Vemis^ they may, with 
refpedt to the centre, be calculated in the lame manner as thole of 
Mercury were 5 but leeing the diameter of Venus is pretty large, 
and the parallaxes may caufe a confiderable difference as to the time, 
there mufl neceffarily be a peculiar calculation for each place : The 
diameter of Venus is fo great, that whilffc fhe adheres to the 
limb of the fun, almoft 20 minutes of time are fpent, viz. when 
fhe diredlly enters the fun 5 but falling obliquely into him, fhc 
makes a longer ftay on his limb: Her diameter, according to the 
obfervation o£ Horror ^ is i' I8'^ when fhe is in conjun61:ion with 
the fun at the afcending node 5 and i' 12'' at the delcending node. 
The principal ufe of thele conjun6tions is, accurately to deter- 
mine the diftance of the fun from the earth or his parallax, which 
aftronomers have by leveral methods attempted in vain, whilfl 
the fmallnefs of the angles fought do ealily elude the nicefl inftru- 
mentsj but in obferving the ingrels of Vefius into, and egrefs 
from, the fun, the fpace of time between the moments of the 
internal conta£is may be obtained to a fecond of time, that is, to 
j^- of a fecond, or 4'" of the obferved arch, by means of an ordi- 
nary tcleicope and clock that goes accurately for fix or eight 
hours. 
Ti^e "ProduEiion of Tadpoles 5 by Mr. Rich. \Yaner. Phil. 
Tranl] >^° 195. p. 525. 
MR. Walleriook fome frog-fpawn out of a ditch, v/hich, he 
fuppoled, might have iDeen fpawned about 14 days, and 
kept it in a galley-pot of water, which he ihifted every day or 
two, and kept them in a Vv^indow where the fun fliined fome part 
of the day 3 at firft they appeared as in Fig. 5. Plate I. being a 
round 
