fixed between systematic science and elusive fact. I knew, for
example, that in science, whether it be subject XII., Organic
Chemistry, or subject XVII., Animal Physiology, when you blow into a
glass of lime-water it instantly becomes cloudy, and if you continue
to blow it clears again, whereas in truth you may blow into the
stuff from the lime-water bottle until you are crimson in the face
and painful under the ears, and it never becomes cloudy at all. And
I knew, too, that in science if you put potassium chlorate into a
retort and heat it over a Bunsen burner, oxygen is disengaged and
may be collected over water, whereas in real life if you do anything
of the sort the vessel cracks with a loud report, the potassium
chlorate descends sizzling upon the flame, the experimenter says
"Oh! Damn!" with astonishing heartiness and distinctness, and a lady
student in the back seats gets up and leaves the room.

Science is the organised conquest of Nature, and I can quite
understand that ancient libertine refusing to co-operate in her own
undoing. And I can quite understand, too, my father's preference
for what he called an illustrative experiment, which was simply an
arrangement of the apparatus in front of the class with nothing
whatever by way of material, and the Bunsen burner clean and cool,
and then a slow luminous description of just what you did put in it
when you were so ill-advised as to carry the affair beyond
illustration, and just exactly what ought anyhow to happen when you
did. He had considerable powers of vivid expression, so that in
this way he could make us see all he described. The class, freed
from any unpleasant nervous tension, could draw this still life
without flinching, and if any part was too difficult to draw, then
my father would produce a simplified version on the blackboard to be
copied instead. And he would also write on the blackboard any