_Note_--The reception of the original work of Bergh while reading the proofs of these pages has enabled me to correct several errors of previous writers, but it was too late to incorporate here the additional material which Bergh's work affords. This will enable me to add, in a future publication, some historical data which have never appeared in English and which are necessary to complete the record. I desire in this place to express my gratitude for and appreciation of the liberality of the authorities of that ancient seat of learning, the University of Upsala, as exhibited in their willingness to send such a valuable document to a foreign student half around the world for purposes of historical research. SUPPLEMENTARY NOTE BY MARCUS BAKER. ON THE ALLEGED OBSERVATION OF A LUNAR ECLIPSE BY BERING IN 1728-9. Bering was in Eastern Siberia, Kamchatka and the adjacent waters in 1728 and 1729. Could he have observed a lunar eclipse there at that time? According to the ephemeris of Manfred[1] published at Bonn in 1725 there were two partial eclipses of the moon visible in Europe in 1728, and two total eclipses of the moon in 1729. [Footnote 1: Manfredius (Eustachius). Novissimae ephemerides motuum coelestium e Cassinianis tabulis ad meridianum Bononiae supputatae auctoribus Eustachio Manfredio (etc.) Tomus 1. ex anno 1726 in annum 1737 (etc.) 4° _Bononiae_, MDCCXXV.] In regard to these four eclipses the ephemeris furnishes the following data: | 1728, | 1728, | 1729, | 1729, | Feb. 24. | Aug. 19. | Feb. 13. | Aug. 8. -------------------+-----------+-----------+-----------+----------- Eclipse begins | 18^h 32^m | 4^h 07^m | 7^h 45^m | 12^h 02^m Total immersion | -- -- | -- -- | 8 46 | 13 02 Middle of eclipse | 20 0 | 5 35 | 9 35 | 13 52 Emersion begins | -- -- | -- -- | 10 24 | 14 42 Eclipse ends | 21 29 | 7 03 | 11 25 | 15 42 -------------------+-----------+-----------+-----------+----------- Digits eclipsed | 9 51 S.| 7 45 N.| 19 46 | 19 44 S. Sun rises | 18 36 | -- -- | -- -- | -- -- Sun sets | -- -- | 6 49 | -- -- | -- -- Eclipse | Partial | Partial | Total | Total. -------------------+-----------+-----------+-----------+----------- Sun's declination | -9° 38' | +12° 42' | -13° 16' | +16° 09' " hourly motion | + 0.9 | - 0.8 | + 0.8 | - 0.7 -------------------+-----------+-----------+-----------+----------- In this table the calendar is Gregorian, the time is apparent or true sun time, the day is reckoned from noon and the hours are counted continuously through the entire 24. The present observatory in Bonn is in Latitude 50° 43' 45" N. Longitude 0^h 28^m 23^s E. from Greenwich.