■\1 "m^J^- i^ -^ t ^ '^ -rr. 



ASTRONOMICAL 



P z\ P E 



RS. 



159 



uiicMurbed by clouds till about half an hour after three, 

 which gave us an opportunity, as favorable as could be 

 dcfired, not only for obferviug the external and internal 

 contads at the ingrefs, but alfo for making fome material 

 micrometer obfervations. 



The external contad was noted to the very fame inflant 



I 

 f 



of time by all the three obfervers without having any com 

 municatloa with each other; the fame method, of giving 

 fignals to perfons ftationcd hj the clock, being purfued 

 now, as at the tranfit of Venus. 

 Mr, Rittenhoujt 



Mr 



u 



Mr 



foon 



er. 



ferve the conta£ls\ but he gave a ready affiftauce in the 



parts of the bufmcfs. 



The whole work of the day Hands as follows^ 



VIZ. 



1769. Apparent time. 



D. h. m. Inches, aoths. Tooths. 



Nov. 9. 9. ff^yi'X sun^.diam. \ f J3. ^ 7 



9. Z$ ihtlo, i i 3. 13. 6 



Mean of thefe gives Q's diam..:=3»'. %o",\ 



per micrometer. 



P. M. 



a. zs- i; 



Firft external contad. 



f Dr. Smith, with a a f , rcfle(5lor. Miignifying power 200. 

 -J Mr. Lukcns, with a 4a f. refraaor. Magnifying power 140. 

 cMr. Ritteiihoufd, with a 36 f. refraaor. Magiufying power X44 



Firft internal contad. 



3t- 3^- .^3 



By Mr. Lukcna, 



By Ur, Smith, autl 

 Mr. Kittcnhoule. 



Each ohferver having the ianie telefcopes, 

 and magnifying powers, as at the external 

 coatad:. 



Micrometer meafures of the lead dillancc of the ncarcfl 



limhs of the Sun and Mercury. 



Apparent time 

 H. m. Ice. 

 3. %, 44 



3. 10- 9 



3. 31. n 



4, zz^ ao 



Inches, 2a|ha. jooths. 

 0. 5. 04 

 0. 6. 1% 

 o, 8. I 

 0. 10. o 

 0. iS. II 



Value in 

 M. Sec. 



a* 50,5 



3' 3^.^4 

 4. 23>7B 

 8. 7,44 



h 



From 



/ 



31' paft three, the Sun was conftantly obfcured 



led with him, 'till about ^o' paft 



in a cloud that defcenc 



3 



pal 



four, at which time he Ihone out for abodt 3'. During 



this 



