ematical astronomy. We did not make it, for we know
nothing of mathematics whatever; therefore, it was made by the only
person to whom it can rationally be ascribed, namely Herschel the
astronomer, its only avowed and undeniable author.' In reality,
notwithstanding this convincing argument, the problem was stolen by
Locke from a paper by Olbers, shortly before published, and gave the
method followed by Beer and Maedler throughout their selenographical
researches in 1833-37.

[50] I had at the same time the good fortune to satisfy in equal degree,
though quite unexpectedly, an English student of the sun, who at that
time bore me no great good-will. Something in the article chanced to
suggest that it came from another, presumably a rival, hand; while an
essay which appeared about the same time (the spring of 1872) was
commonly but erroneously attributed to me. Accordingly, a leading
article in _Nature_ was devoted to the annihilation of the writer
supposed to be myself, and to the lavish and quite undeserved laudation
of the article I had written, which was selected as typifying all the
good qualities which an article of the kind should possess. Those
acquainted with the facts were not a little amused by the mistake.

[51] The Astronomer-Royal once told me that he had found that few
persons have a clear conception of the fact that the stars rise and set.
Still fewer know how the stars move, which stars rise and set, which are
always above the horizon, which move on large circles, which on small
ones; though a few hours' observation on half-a-dozen nights in the year
(such observations being continuous, but made only at hourly intervals)
would show dearly how the stars move. It is odd to find even some who
write about astronomy making mistakes on matters so elementary. For
instance, in a primer of astronomy recently published, it is stated that
the stars which pass overhead in London rise and set on a slant--the
real fact being that _those_ stars never rise or set at all, never
coming within some two dozen moon-breadths of the horizon.

[52] In passing let me note that, of course, I am not discussing the
arguments of paradoxists with the remotest idea of disproving them. They
are not, in reality, worth the trouble. But they show where the general
reader of astronomical text-books, and other such works, is likely to go
astray, and thus conveniently indicate matters whose explanation may be
useful or interesting.

[53] S