VOL. LIX.} PHILOSOPHICAL TfiANSACTIONS. 629 



that attended the planet before the apparent contact ; but that instead of it there 

 appeared a small circle of light, somewhat more luminous than the surrounding 

 parts of the sun. Mr. Shuckburgh also observed the beginning of the eclipse 

 at IS*" as"* 51', and the end at 20'' 18*" 38', with the appulse of the moon to 

 several of the spots. 



In an unfurnished room of the hospital, that commanded the north-west part 

 of the horizon, Mr. Nikitin of St. Mary Hall, and inspector of the Russian 

 gentlemen sent here for their education by the empress of Russia, and Mr. Wil- 

 liamson, of St. Alban Hall, both well versed in the mathematics, made the 

 annexed observations of the transit, with istext. cont. Ingress. 



a reflector of 10 inches, and a refractor of Mr. Nikitin 

 8 feet. ^'- Williamson 



7h 6m 4+s [ 7h 24m 158| 

 7 6 29 I 7 24 lOJ 



The transit and the eclipse were also observed here by the Rev. Mr. Horsley, 

 F. R. s. and Mr. Cyril Jackson, a. b. and student of Christ Church. 



The latitude of Oxford is 51° 45' 15", as determined by himself, from several 

 observations of the pole star, both above and below the pole, with an excellent 

 mural quadrant, of 32 inches, made by Mr. Bird ; the focal length of the 

 telescope being 34 inches. Mr. H. is the rather induced at present to mention 

 this, as the latitude of Oxford, given by Mr. de la Lande in the Connoissance 

 des temps, and attributed to him, was determined by the late Professor Bliss, 

 from observations made with a smaller and less perfect instrument. The longi- 

 tude of Oxford is 5™ 3' or 5"" 4' to the west of Greenwich, the former quantity 

 being deduced from a comparison of the sun's eclipse, observed by himself, with 

 Mr. Short's observation, an allowance being made in the computation for the 

 figure of the earth, in the effect of the moon's parallax. 



XXI f^. Fenus observed on the Sun at Oxford, June 3, 1769. Bi/ Samuel 

 Horsley, LL.B., F.R.S. p. 183. 



Mr. Horsley's regulator was moved to the place of observation on Wednesday 

 evening, and set a going on Thursday ; and between that time and 9 o'clock on 

 Sunday morning, many comparisons were made of it with Mr. Hornsby's obser- 

 vatory clock, by which its rate of going and distance for Mr. Hornsby's clock, 

 at the time of observation, were pretty well determined. At 10"" before 7, by his 

 regulator, he began to observe and to count the seconds, and about 3*" and 3 or 

 4' after 7, he described a very small black notch on that part of the sun's limb 

 where he expected the planet; but it was then so small, that he was in doubt 

 whether it was any thing more than an appearance occasioned by the horizontal 

 vapours, which were more copious than he could have wished, and made the sun's 

 edge, as usual, appear ragged in many parts. But by 5*" after T, this notch was 

 grown so large, that no doubt remained that it was the planet. 



This was Mr. H.'s observation of the external contact, which he wrote how- 



