his lecture the object of which he is
treating; while the orator, who cannot make any conditions with his
audience, and who needs above everything sympathy, to secure it on his
side, must regulate his action and treatment according to the subjects on
which he turns his discourse. The hearers of the professor have already
attended his lectures, and will attend them again; they only want
fragments that will form a whole after having been linked to the
preceding lectures. The audience of the orator is continually renewed;
it comes unprepared, and perhaps will not return; accordingly in every
address the orator must finish what he wishes to do; each of his
harangues must form a whole and contain expressly and entirely his
conclusion.

It is not therefore surprising that a dogmatic composition or address,
however solid, should not have any success either in conversation or in
the pulpit, nor that a fine diction, whatever wit it may contain, should
not bear fruit in a professor's chair. It is not surprising that the
fashionable world should not read writings that stand out in relief in
the scientific world, and that the scholar and the man of science are
ignorant of works belonging to the school of worldly people that are
devoured greedily by all lovers of the beautiful. Each of these works
may be entitled to admiration in the circle to which it belongs; and more
than this, both, fundamentally, may be quite of equal value; but it would
be requiring an impossibility to expect that the work which demands all
the application of the thinker should at the same time offer an easy
recreation to the man who is only a fine wit.

For the same reason I consider that it is hurtful to choose for the
instruction of youth books in which scientific matters are clothed in an
attractive style. I do not speak here of those in which the substance is
sacrificed to the form, but of certain writings really excellent, which
are sufficiently well digested to stand the strictest examination, but
which do not offer their proofs by their very form. No doubt books of
this kind attain their end, they are read; but this is always at the cost
of a more important end, the end for which they ought to be read. In
this sort of reading the understanding is never exercised save in as far
as it agrees with the fancy; it does not learn to distinguish the form
from the substance, nor to act alone as pure understanding. And yet the
exercise of the pure understanding