onstrates that the way out of the
apparently irreconcilable contradiction of theory and observation in
this matter does not lie in the direction of discrediting the
observations, as he is inclined to do. On the contrary, the result is
a beautiful vindication of the trustworthiness of the latter, and, at
the same time, of the theory that demands an invariable rate of
motion; providing a perfectly fitting key to the riddle by showing
that another cause has intervened to produce the variability of the
period. I feel confident that Professor Newcomb will agree with the
reality of the explanation here set forth, and will reconsider his
view that the perturbations in the position of the Pole must be of
the nature of chance accumulations of motion, a view which he then
considered necessary to the maintenance of the constancy in the
period of latitude-variation."

[Sidenote: The final paper.]

The paper from which these words are taken appeared on November 4, 1892.
The next paper on the main theme did not appear till a year later, though
much work was being done in the meantime on the constant of aberration and
other matters arising immediately after the discovery. On November 14,
1893, Mr. Chandler winds up the series of eight papers "On the Variation
of Latitude," which he had commenced just two years before. His work was
by no means done; rather was it only beginning, for the torch he had lit
illuminated many dark corners. But he rightly regarded his discovery as
now so firmly established that the series of papers dealing with it as
still under consideration might be terminated. In this final paper he
first devotes the most careful attention to one point of detail. He had
shown earlier in the series that the North Pole must be revolving from
West to East, and not from East to West; but this was when the motion was
supposed to be simple and not complex, and it was necessary to re-examine
the question of direction for each of the components. After establishing
conclusively that the original direction holds for each of the components,
he almost apologises for the trouble he has taken, thus:--

"It is therefore proved beyond reasonable doubt that the directions
of the rotations is from West to East in both elements; whence the
general form of the equation for the variation of latitude adopted in
_A. J._, 284, p. 154, eq. (19). It may be thought