careful discussion of the observations showed
that there was no oscillation in such a period. Now we know that the
theory itself was wrong, or rather was founded upon a mistaken assumption;
and that the facts when properly examined show clearly a distinct movement
of the North Pole, not a very large one, for all its movements take place
within the area occupied by a moderate-sized room, but still a movement
easily measurable by astronomical observations, and Mr. Chandler was the
first to point out the law of these movements, and very possibly the first
to suspect them.

[Sidenote: Chandler's papers.]

With these few words of explanation I will let Mr. Chandler tell his own
story. His first paper appeared in the _Astronomical Journal_ in November
1891, and is courageously headed, "On the Variation of Latitude"--I say
courageously, because at that time it was believed that the latitude did
_not_ vary, and Mr. Chandler himself was only in possession of a small
portion of the facts. They unravelled themselves as he went forward; but
he felt that he had firm hold of the end of the thread, and he faced the
world confidently in that belief. He begins thus:--

[Sidenote: First signs of change.]

"In the determination of the latitude of Cambridge[5] with the
Almucantar, about six years and a half ago, it was shown that the
observed values, arranged according to nights of observation,
exhibited a decided and curious progression throughout the series,
the earlier values being small, the later ones large, and the range
from November 1884 to April 1885 being about four-tenths of a second.
There was no known or imaginable instrumental or personal cause for
this phenomenon, yet the only alternative seemed to be an inference
that the latitude had actually changed. This seemed at the time too
bold an inference to place upon record, and I therefore left the
results to speak for themselves. The subsequent continuation of the
series of observations to the end of June 1885 gave a maximum about
May 1, while the discussion of the previous observations from May to
November 1884 gave a minimum about September 1, indicating a range of
0".7 within a half-period of about seven months."

Mr. Chandler then gives some figures in support of these statements,
presenting them with the clearness which is so well marked a feature of
the whole series of papers, and conclude