Tranjit of Mercury. 1S7 



Utrecht, Nov. 10. — M. van Utenhoven ohferved yefterday 

 at the obfervatory of this academy, the ingrefs of Mercury 

 at 12 hours 17 iiiinutes 53 feconds, and the egrefs or the end 

 of the tranfit of ihe planet over the fun's dilk at la hours 

 19 minutes 28 feconds true time. M. Timmers of Rotter- 

 dam, a ftudcnt here, obferved the paffage of Mercury over 

 the meridian to be 15 feconds after the fun's limb. He ob- 

 ferved alfo ieveral times the contaA of the Sun and Mercury 

 on the horizontal and vertical threads of a quadrant by Bird, 

 in order to calculate the time of the conjunfition according 

 to the method of L'Ifle le Cadet. This phenomenon, which 

 will not be vifible again in this republic till the 4th of May 

 1832, was rendered^much more important by the appearance 

 of a creat many folar fpots ; a colleftion of fuch fpots, one or 

 two of which feemed to be larger than Mercury. 



Ley den, Nov. 10. — Yetterday morning 1 had the fatisfac- 

 tion, with M. Bifdoni, M. van der Meer, and feveral of my 

 pupils, to obferve at the obfervatory of our univerfiiy the 

 palfage of Mercury over the fun's dilk. Mercury it appears 

 muft'have been oii'the fun's difk before fun-rife, as the clouds 

 prevented us from feeing that luminary till half after nine. 

 The fun having then broke through theclouds for fome time, 

 the planet was plainly feea on the fun's difk as a black, 

 round, fliarply defined body, and could be eafily diftinguin)ccl 

 from the folar fpots, a great many of which were then vifible 

 on the fun's dilk. The planet took its courfc under a great 

 many of the principal fpots, and, when it approached the 

 fun's limb, feemed to have a fomcwhat elongated form. I 

 obferved the cnntadl at the time of ingrefs to be at 12 hours 



15 minutes 6 feconds, and at the time of cgrefs at 12 hours 



16 minutes 40 feconds, and therefore that of the planet's was 

 J 2 hours 15 minutes 53 feconds, true civil time. The. 

 planet employed 9+ feconds from the lime of ingrefs to that 

 of its egrefs, which agrees vi ry well with calculation if the 

 diameter be taken at . 1 feconds. I previoudy obferved the 

 planet's pallatre of the meridian with our meridian circle on 

 the 8th of November, 33 hours 43 minutes 8 feconds mean 

 time. I have no dou'r)t that this tranlit will enable allrono- 

 mers to improve or conllrm the tables of Mercury. 



Van Bkf.ck Calkokn. 

 Enfchcde, Nov. 13. — Obfervation of the tranfit of Mercury 

 over the fun's difk at Enfchede. on the 4th of Novem- 

 ber 1802, with the day teleitoiie and an achromalie te!c- 

 feopc, whieli magnilics the diameter /jO times, the clock 

 beinij biouj^lil to true lime by a incridiau line: but th<re 



