r, a fairly
good criterion may be had in the list of the monographs he has
written.[222] It is the gift of seeing the important problems, and the
taste for their treatment, as well as the power of solving them, which,
in all the sciences, raise men to the first rank. But let us suppose the
subject has been rationally chosen. Every monograph, in order to be
useful--that is, capable of being fully turned to account--should
conform to three rules: (1) in a monograph every historical fact derived
from documents should only be presented accompanied by a reference to
the documents from which it is taken, and an estimate of the value of
these documents;[223] (2) chronological order should be followed as far
as possible, because this is the order in which we know that the facts
occurred, and by which we are guided in searching for causes and
effects; (3) the title of the monograph must enable its subject to be
known with exactitude: we cannot protest too strongly against those
incomplete or fancy titles which so unnecessarily complicate
bibliographical searches. A fourth rule has been laid down; it has been
said "a monograph is useful only when it exhausts the subject"; but it
is quite legitimate to do temporary work with documents which one has at
one's disposal, even when there is reason to believe that others exist,
provided always that precise notice is given as to what documents have
been employed.

Any one who has tact will see that, in a monograph, the apparatus of
demonstration, while needing to be complete, ought to be reduced to what
is strictly necessary. Sobriety is imperative; all parading of erudition
which might have been spared without inconvenience is odious.[224] In
history it often happens that the best executed monographs furnish no
other result than the proof that knowledge is impossible. It is
necessary to resist the desire which leads some to round off with
subjective, ambitious, and vague conclusions monographs which will not
bear them.[225] The proper conclusion of a good monograph is the
balance-sheet of the results obtained by it and the points left
doubtful. A monograph made on these principles may grow antiquated, but
it will not fall to pieces, and its author will never need to blush for
it.

(2) Works of a general character are addressed either to students or to
the general public.

_A._ General works intended principally for students and specialists now
appear in the form of "repertories," "m