/ 



M 



PAPERS. 



45 



" On confidermg the matter in this view, I am inclined 

 to think that the firft external contadt did not really hap- 

 pen 'till at leaf! three feconds after 1 firft perceived the 

 jagged obfcuration on the Sun'-s Hmb: and then it would 



be at 



2^. 13^-50^^ apparent time 



" But if aftronomers agree to fix the time of the firft 

 Gontad at the beginning of that obfcuration, I think it is 

 probable the contad may have happened two or three fe- 

 conds before I difcerned that obfcuration : In which cafe, 



the coHtaa may be faid to take place at 2''. 13'. 44" ap- 

 parent time. . 



"In determining on the manner in which I (hould judge 

 of the internal contaa, I confidered that after Venus fliould 

 move on the Sun's difk with half her diameter, the horned 

 points occafioned thereby in the Sun's limb would appear 

 more acute, and approach nearer to each other as the planet 

 proceeded till the points Oiould adually unite. From this 

 refleaion I was induced to think, that the inftant of the 

 clofing of thofe points ought to be fixed on as the precife 

 time of the internal contaft; becaufe Venus muft then have 

 palled the Sun's limb with her whole diameter, and both 

 their circumferences^ or limbs, might be faid to coincide. 



" I therefore carefully obferved the progrefs of the plan- 

 et, and faw very diftindly, as flie moved onwards, that 

 the illuminated points of the Sun's limb became better de- 

 fined; and when they approached fo near each other as to 

 be within about 8 feconds of touching, which was at 2\ 

 2,1' . 26" ap. time, I lieard one of the obfervers call out, 

 contatl\ but as his obfervation did not fcem to agree with 

 the manner which I had fixed for judging of the contaft, 

 I continued viewing with the clofeft attention, in order to 

 fix the time of contad according to the idea I had formed 

 of it; and at 2\ 3 1 ' 34". ap. timel could fcarcely diftinguifli 

 the illuminated points of the Sun's limb to be any lono-er 

 feparate; for In.two feconds more they appeared to befo far 

 clofed as to form a fingle thread of light on that part of the 

 Suu's limb, which a few feconds before had been cdipfed. 



I therefore 



i 



v>± 



lJ^ 



-/^v 



v.- 



