fest utility. In the large and
heterogeneous family of those who labour to promote the progress of
historical study, the makers of descriptive catalogues and indexes form
a section to themselves. When they devote themselves exclusively to
their art they acquire by practice, as one might expect, a high degree
of dexterity.

While waiting for the fact to be clearly recognised that the time is
opportune for pushing vigorously in every country the construction of a
general catalogue of historical documents, we may indicate a palliative:
it is important that scholars and historians, especially novices, should
be accurately informed of the state of the instruments of research which
are at their disposal, and be regularly apprised of any improvements
that from time to time may be made in them. Experience and accident have
been for a long time trusted to supply this information; but empirical
knowledge, besides being costly, as we have already pointed out, is
almost always imperfect. Recently the task has been undertaken of
constructing catalogues of catalogues--critical and systematic lists of
all the catalogues in existence. There can be no doubt that few
bibliographical enterprises have possessed, in so great a degree, the
character of general utility.

But scholars and historians often need, in respect of documents,
information not usually supplied by descriptive catalogues; they wish,
for example, to know whether such and such a document is known or not,
whether it has already been critically dealt with, annotated, or
utilised.[41] This information can only be found in the works of former
scholars and historians. In order to become acquainted with these
works, recourse must be had to those "bibliographical repertories,"
properly so called, of all kinds, compiled from very different points of
view, which have already been published. Among the indispensable
instruments of Heuristic must thus be reckoned bibliographical
repertories of historical literature, as well as repertories of
catalogues of original documents.

To supply the classified list of all those repertories (repertories of
catalogues, bibliographical repertories, properly so called), together
with other appropriate information, in order to save students from
mistakes and waste of time, is the object of what we are at liberty to
call the "science of repertories," or "historical bibliography."
Professor Bernheim has published a preliminary sketch[42] of it, whi