; indeed, most astronomical projects do
ultimately resolve themselves into questions of money; and I fear the
world looks upon scientific men as insatiable in this respect. One can
only hope that on the whole the money is expended so as to give a
satisfactory return. In this instance I have no hesitation in saying that
an immediate return of value for a comparatively modest expenditure is
practically certain, if only in some way we can get the means of making
the observations.

It would be natural, at the conclusion of this brief review of some types
of astronomical discovery, to summarise the lessons indicated: but there
is the important difficulty that there appear to be none. It has been
pointed out as we proceeded that what seemed to be a safe deduction from
one piece of history has been flatly contradicted by another; no sooner
have we learnt that important results may be obtained by pursuing steadily
a line of work in spite of the fact that it seems to have become tedious
and unprofitable (as in the search for minor planets) than we are
confronted with the possibility that by such simple devotion to the day's
work we may be losing a great opportunity, as Challis did. We can scarcely
go wrong in following up the study of residual phenomena in the wake of
Bradley; but there is the important difficulty that we may be wholly
unable to find a clue for the arrangement of our residuals, as is at
present largely the case in meteorology. And, in general, human
expectations are likely to be quite misleading, as has been shown in the
last two chapters; the discoveries we desire may lie in the direction
precisely opposite to that indicated by the best opinion at present
available. There is no royal road to discovery, and though this statement
may meet with such ready acceptance that it seems scarcely worth making,
it is hoped that there may be sufficient of interest in the illustrations
of its truth.

The one positive conclusion which we may derive from the examples studied
is that discoveries are seldom made without both hard work and conspicuous
ability. A new planet, even as large as Uranus, does not reveal itself to
a passive observer: thirteen times it may appear to such a one without
fear of detection, until at last it encounters an alert Herschel, who
suspects, tests, and verifies, and even then announces a comet--so little
did he realise the whole truth. Fifteen years of unrequited labour before
Astraea was found, ni