. Quite early in life I acquired an
almost ineradicable sense of the unscientific perversity of Nature and
the impassable gulf that is 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
exceptionally difficult but grant-earning words, such as "empyreumatic"
or "botryoidal."

Some words in constant use he rarely explained. I remember once sticking
up my hand and asking him in the full flow of description, "Please, sir,
what is flocculent?"

"The precipitate is."

"Yes, sir, but what does it mean?"

"Oh! flocculent!" said my father, "flocculent! Why--" he extended his
hand and arm and twiddled his fingers fo