Newcomb further showed that small residual irregularities are still found in the movements of our satellite, inexplicable either by any known gravitational influence, or by any uniform value that could be assigned to secular acceleration.[963] If set down to the account of imperfections in the "time-keeping" of the earth, it could only be on the arbitrary supposition of fluctuations in its rate of going themselves needing explanation. This, it is true, might be found in very slight changes of figure,[964] not altogether unlikely to occur. But into this cloudy and speculative region astronomers for the present decline to penetrate. They prefer, if possible, to deal only with calculable causes, and thus to preserve for their "most perfect of sciences" its special prerogative of assured prediction.
FOOTNOTES:
[796] Neueste Beyträge zur Erweiterung der Sternkunde, Bd. iii., p. 14 (1800).
[797] Ibid., p. 24.
[798] Phil. Trans., vol. xciii., p. 215.
[799] Mem. Roy. Astr. Soc., vol. vi., p. 116.
[800] Month. Not., vol. xix., pp. 11, 25.
[801] Ibid., vol. xxxviii., p. 398.
[802] Am. Jour. of Sc., vol. xvi., p. 124.