n the
polar motion. If, on the contrary, they occur at times successively
corresponding to the differences of longitude, the presumption is
equally fatal to the hypothesis that they can possibly be due to
temperature variation as affecting instrumental measurement. But the
facts given in the foregoing section correspond most distinctly to
the latter condition. Therefore, unless additional facts can be
brought to disprove successively these observed results, we may
dismiss for ever the bugbear which has undoubtedly led many to
distrust the reality of the annual component of the
latitude-variation, while they admit the existence of the 427-day
term."

[Sidenote: Consequences of the discovery.]

[Sidenote: Suspected observers acquitted.]

At this point we must leave the fascinating account of the manner in which
this great discovery was established, in the teeth of opposition such as
might have dismayed and dissuaded a less clear-sighted or courageous man.
It is my purpose to lay more stress upon the method of making the
discovery than upon its results; but we may afford a brief glance at some
of the consequences which have already begun to flow from this step in
advance. Some of them have indeed already come before us, especially that
large class represented by the explanation of anomalies in series of
observations which had been put aside as inexplicable. We have seen how
the observations made in Russia, or in Washington, or at Greenwich, in all
of which there was some puzzling error, were immediately straightened out
when Chandler applied his new rule to them. We in England have special
cause to be grateful to Chandler; not only has he demonstrated more
clearly than ever the greatness of Bradley, but he has rehabilitated Pond,
the Astronomer Royal of the beginning of the nineteenth century; showing
that his observations, which had been condemned as in some way erroneous,
were really far more accurate than might have been expected; and further
he has shown that the beautiful instrument designed by Airy, and called
the Reflex Zenith Tube, which seemed to have unaccountably failed in the
purpose for which it was designed, was really all the time accumulating
observations of this new phenomenon, the Variation of Latitude. Instead of
Airy having failed in his design, he had in Chandler's words "builded
better than he knew."

[Sidenote: Constant of Aberration improved