It is much to be desired, both for the Athenaeum and for the public, that such an erroneous statement should not remain uncorrected. And I would suggest that a correction by the Editor would be just and graceful, and would tend to support the Athenaeum in that high position which it has usually maintained. I am, dear Sir, Yours very faithfully, G.B. AIRY. _Hepworth Dixon, Esq._ 1859 "The Report to the Visitors states that 'The Lunar Reductions with amended elements (especially parallax) for correction of Observations from 1831 to 1851 are now completed. It is, I think, matter of congratulation to the Observatory and to Astronomy, that there are now exhibited the results of uninterrupted Lunar Observations extending through more than a century, made at the same place, reduced under the same superintendence and on the same general principles, and compared throughout with the same theoretical Tables.'--After reference to the great value of the Greenwich Lunar Observations to Prof. Hansen in constructing his Tables, and to the liberality of the British Government in their grants to Hansen, the Report continues thus: 'A strict comparison of Hansen's Tables with the Greenwich Observations of late years, both meridional and extra-meridional, was commenced. The same observations had, in the daily routine of the Observatory, been compared with the Nautical Almanac or Burckhardt's Tables. The result for one year only (1852) has yet reached me, but it is most remarkable. The sum of squares of residual errors with Hansen's Tables is only one-eighth part of that with Burckhardt's Tables. When it is remembered that in this is included the entire effect of errors and irregularities of observation, we shall be justified in considering Hansen's Tables as nearly perfect. So great a step, to the best of my knowledge, has never been made in numerical physical theory. I have cited this at length, not only as interesting to the Visitors from the circumstance that we have on our side contributed to this great advance, but also because an innovation, peculiar to this Observatory, has in no small degree aided in giving a decisive character to the comparison. I have never concealed my opinion that the introduction and vigorous use of the Altazimuth for observations of the Moon is the most important addition to the system of the Observatory that has been made for many years. The largest errors of Burckhardt's Tables were put in evidence almost always by the Altazimuth Observations, in portions of the Moon's Orbit which could not be touched by the meridional instruments; they amounted sometimes to nearly 40" of arc, and they naturally became the crucial errors for distinction between Burckhardt's and Hansen's Tables. Those errors are in all cases corrected with great accuracy by Hansen's Tables.'--The Report concludes with the following paragraph: 'With the inauguration of the