, good-bye." And she drifted out.

I went on thinking.

"No," I said to myself, "I'm on the wrong tack." So I began again:--

"SOME YORKSHIRE POT-HOLES

"_Lecture delivered before the Blanktown Literary and Philosophical
Society, Tuesday, December 8th_.

"_My Lord Mayor, my Lords_--"

"I don't want to interrupt," said Celia coming in suddenly, "but--oh,
what's a pot-hole?"

"A curious underground cavern sometimes found in the North."

"Aren't caverns always underground? But you're busy. Will you be in for
lunch?"

"I shall be writing my lecture all day," I said busily.

At lunch I decided to have a little financial talk with Celia.

"What I feel is this," I said. "At most I can ask ten guineas for my
lecture. Now my expense all the way to the North, with a night at an
hotel, will be at least five pounds."

"Five-pounds-ten profit," said Celia. "Not bad."

"Ah, but wait. I have never spoken in public before. In an immense hall,
whose acoustics--"

"Who are they?"

"Well, never mind. What I mean is that I shall want some elocution
lessons. Say five, at a guinea each."

"That still leaves five shillings."

"If only it left that, it might be worth it. But there's a new white
waistcoat. An audience soon gets tired of a lecture, and then there's
nothing for the wakeful ones to concentrate on but the white waistcoat of
the lecturer. It must be of a virgin whiteness. Say thirty-five
shillings. So I lose thirty shillings by it. Can I afford so much?"

"But you gain the acoustics and the waistcoat."

"True. Of course, if you insist--"

"Oh, you _must_," said Celia.

So I returned to the library. By tea-time I had got as far as this:--

"ADVENTURES WITH A CAMERA IN SOMALILAND

"_Lecture delivered before the Blanktown Literary and Philo_--"

And then I had an idea. This time a brilliant one.

"Celia," I said at tea, "I have been wondering whether I ought to take
advantage of your generosity."

"What generosity?"

"In letting me deliver this lecture."

"It isn't generosity, it's swank. I want to be able to tell everybody."

"Ah, but the sacrifices you are making."

"Am I?" said Celia, with interest.

"Of course you are. Consider. I ask a fee of ten guineas. They cannot
possibly charge more than a shilling a head to listen to me. It would
be robbery. So that if there is to be a profit at all, as presumably they
anticipate, I shall have a gate of at least two hundred and fifty."

"I should _ho