THE TRANSATLANTIC LONGITUDE. 5 



of the Astronomer Royal concerning the reductions of the Greenwich Lnnar 

 Observations appeared soon after, and indicated^ that Burckhardt's coef&cient 

 required an increase by its twelve-hundredth part, or 2". 85, thus dissipating any 

 yet remaining doubts as to the necessity of a large diminution of all American longi- 

 tudes counted from a European meridian. 



We thus have at present, from observations of eclipses and occvdtations — 



Walker,'' corrected value from observations before 1843 . . S"" 8™ 11M4 



Peirce,^ from eclipse of 1851, July 28 11.51 



Peirce,* from emersions of Pleiades, 1839, Sept. 26 . . . 11.45 ± 0.3 



Peirce,= " " " 1856— 18G1 . . . 13.13 



but neither of the last three determinations is considered by Prof. Peirce as final. 



II. From Moon Culminations : — 



Walker,' from Cambridge observations 1843 — 45 



5"' 8» 10'. 01 



Loomis,' " Hudson " 1838—44 ... -9.3 



Gilliss,^ " Capitol Hill " 1838—42 . . . 10.04 



Walker,8 " Washington " 1845 . . . 9.60 



Newcomb," from " " 1846—60 . . • 11.6 ± 0.4 



Newcomb,'" " " " 1862—3 ... 9.8 



Walker considered 9'. 96 as the most probable value from moon-culminations, and 

 Newcomb assigned 11'. 1 as that indicated by those observed at the Naval Observa- 

 tory from 1846 to 1863, inclusive. 



III. From chronometers transported between Boston and Livei-jpool. 



Indiscriminate mean" from 313 chronometers previous to 1849 . 5'' 8" 12'.46 



Bond's" discussion of 115 chronometers. Expedition of 1849 . 11.14 



Walker's" " " " " " . 12.00 



Bond's'^ " " " " " . 12.20 ± 0.20 



Bond's'* " of 52 chronometers, 6 trips, Expedition of 1855 13.43 ± 0.19 



All of these values require to be increased by 0'.06, to conform to the new telegra- 

 phic determination by the Astronomer Royal of the longitude between Liverpool 

 and Greenwich. 



The discordance of results which individually would have appeared entitled to full 

 reliance is thus seen to exceed four seconds ; the most recent determinations, and 

 those which would be most relied upon, being among the most discordant. No amount 

 of labor, effort, or expense had been spared by the Coast Survey for its chronome- 

 tric expeditions, inasmuch as the most accurate possible determination of the trans- 



1 Monthly Notices R. Astr. Soc, YIIL 186; Mem. R..Astr. Soc, XYII. 52. 

 " Coast Survey Report, 1851, p. 480. ' Ibid. 1861, p. 195. 



' Ibid. 1861, p. 220. * MS. Coast Survey Report. " Ibid. 1851, p. 480. 



' Astr. Journal, I. 61, using telegraphic longitude of Hudson from Washington as given by 

 Walker, Coast Survey Report, 1851, p. 481. See also Trans. Amer. Phil. Soc, X. 10. 

 « Trans. Am. Philos. Soc, X. 123; Wash. Obs. 1862, vii. 

 8 Wash. Obs. 1862, lii. '° Ibid. 1864, p. 46. 



" Coast Survey Report, 1851, p. 480. " Ibid. 1850, pp. 11, 19. 



" Ibid. 1854, pp. 120, 138, 141. " Ibid. 1856, p. 182. 



