methods of exposition aside. First he posed his pupils with
questions and then dictated model replies.

That was my father's method of instruction. I attended his classes
as an elementary grant-earner from the age of ten until his death,
and it is so I remember him, sitting on the edge of a table,
smothering a yawn occasionally and giving out the infallible
formulae to the industriously scribbling class sitting in rows of
desks before him. Occasionally he would slide to his feet and go to
a blackboard on an easel and draw on that very slowly and
deliberately in coloured chalks a diagram for the class to copy in
coloured pencils, and sometimes he would display a specimen or
arrange an experiment for them to see. The room in the Institute in
which he taught was equipped with a certain amount of apparatus
prescribed as necessary for subject this and subject that by the
Science and Art Department, and this my father would supplement with
maps and diagrams and drawings of his own.

But he never really did experiments, except that in the class in
systematic botany he sometimes made us tease common flowers to
pieces. He did not do experiments if he could possibly help it,
because in the first place they used up time and gas for the Bunsen
burner and good material in a ruinous fashion, and in the second
they were, in his rather careless and sketchy hands, apt to endanger
the apparatus of the Institute and even the lives of his students.
Then thirdly, real experiments involved washing up. And moreover
they always turned out wrong, and sometimes misled the too observant
learner very seriously and opened demoralising controversies. Quite
early in life I acquired an almost ineradicable sense of the
unscientific perversity of Nature and the impassable gulf that is