your mind by reading." A properly composed 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
when I say, that none of the best gifts of science are to be won by
these means. On the contrary, the great benefit which a scientific
education bestows, whether as training or as knowledge, is dependent
upon the extent to which the mind of the student is brought into
immediate contact with facts--upon the degree to which he learns the
habit of appealing directly to Nature, and of acquiring through his
senses concrete images of those properties of things, which are, and
always will be, but approximatively expressed in human language. Our
way of looking at Nature, and of speaking about her, varies from year
to year; but a fact o