course of lectures ought to contain fully as much matter as a student
can assimilate in the time occupied by its delivery; and the teacher
should always recollect that his business is to feed, and not to cram
the intellect. Indeed, I believe that a student who gains from a course
of lectures the simple habit of concentrating his attention upon a
definitely limited series of facts, until they are thoroughly mastered,
has made a step of immeasurable importance.

But, however good lectures may be, and however extensive the course of
reading by which they are followed up, they are but accessories to the
great instrument of scientific teaching--demonstration. If I insist
unweariedly, nay fanatically, upon the importance of physical science
as an educational agent, it is because the study of any branch of
science, if properly conducted, appears to me to fill up a void left by
all other means of education. I have the greatest respect and love for
literature; nothing would grieve me more than to see literary training
other than a very prominent branch of education: indeed, I wish that
real literary discipline were far more attended to than it is; but I
cannot shut my eyes to the fact, that there is a vast difference
between men who have had a purely literary, and those who have had a
sound scientific, training.

Seeking for the cause of this difference, I imagine I can find it in the
fact that, in the world of letters, learning and knowledge are one, and
books are the source of both; whereas in science, as in life, learning
and knowledge are distinct, and the study of things, and not of books,
is the source of the latter.

All that literature has to bestow may be obtained by reading and by
practical exercise in writing and in speaking; but I do not exaggerate