20 



MR. RUMKER'S OBSERVATIONS 



Remarks on the preceding Eclipse. 



Before the end of the eclipse I distinctly saw, on that part of 

 the sun from which the moon parted, this appearance, which 

 could have only arisen from projecting points on the moon's 

 surface. 



The vanishing of the last black spot A was equal to the im- 

 mersion of a fixed star. 



Owing to the oblique direction in which the moon traversed 

 the sun, the diminution of the shade was very slow, so that this 

 eclipse is not well qualified for deducing the geographic longitude, which would 

 be greatly influenced by any small error of the moon's tables in latitude, or an 

 erroneous assumption of the ratio of the earth's axes. Whereas, on the con- 

 trary, this ratio might with considerable accuracy be deduced from the pre- 

 ceding micrometrical measurements, if compared with any corresponding 

 observations made in any part of Asia. 



I take this opportunity of recording the transit of Mercury over the sun's 

 disk, as observed by me the 5th November, 1822. 



h m s h m s 



Immersion of 9 's first limb 13 59 27.0 Emersion of first limb 16 44 23 Sid. Time. 



Complete Immersion 14 2 8 Complete Emersion . . 16 47 22 ■ 



The sun's centre passed over the meridian at 14 38 39.41 



Mercury culminated 14 38 29.9 . 



The declination of J observed with the mural circle whilst the planet passed 

 upon the sun's disk over the meridian was. 



Refraction 



15 43 49.34 

 — 17.80 



15 43 31.44 



Parallax is not applied. 



I subjoin the micrometrical observations ; first in right ascension, or the 

 passages over the middle wire of the micrometer of the sun's limb and centre 

 of y in sidereal time. 



Sun's 1st Limb. 



Mercury. 



Sun's 2d L. 



Sun's 1st Limb. 



Mercury. 



Sun's 2d L, 



Sun's 1st Limb. 



Mercury, Sun's 2d L, 



h 

 14 



2 

 5 

 8 

 11 

 14 

 17 

 22 

 24 



4.65 

 56.5 

 46.5 

 43.5 

 61.2 

 45 

 39.7 

 31 



3 



7 



9 



12 



58 

 7 

 56 

 52 

 15 58.5 

 18 51 

 23 46 

 25 35 



m 

 5 

 8 

 11 

 13 

 17 

 20 



2.5 

 12.5 



2.0 

 59.5 



6.5 



0.5 



26 46.5 



15 



40 



2.7 

 10 

 55 



4.3 



57 58.7 

 57.2 

 5 25.7 



28 42.5 



44 58.5 



48 5.0 



50 50 



50 57 



58 50.7 



1 48.2 



6 14.7 



29 



46 



49 



52 



57 







3 



7 



55.5 



27.7 



26.0 



11 



19.7 



14.7 



12.7 



41.2 



30.7 

 50.2 

 13.7 

 12.7 

 59.9 

 18.2 

 42.4 



18.2 

 37.7 

 59.2 

 56.7 

 42.7 

 0.7 

 23.9 



m 8 

 10 46.2 



17 30.2 



