“I have to read my paper to-night,� he said abruptly. “I really ought to be thinking about it.�
“I do hope it will be a success,� said the girl; “but I rather thought you were always thinking about it.�
“Well, I was—generally,� he said in a rather dazed fashion; and indeed it was probably the first time that he had ever found himself fully conscious of not thinking about it. Of what he was thinking about he was by no means fully conscious.
“I suppose you have to be awfully clever even to understand it,� observed Margery Dale conversationally.
“I don’t know,� he said, slightly stirred to the defensive. “I’m sure I could make you see—I don’t mean you aren’t clever, of course; I mean I’m quite sure you’re clever enough to see—to see anything.�
“Only some sorts of things, I’m afraid,� she said, smiling. “I’m sure your theory has got nothing to do with cows and milking-stools.�
“It’s got to do with anything,� he said eagerly; “with everything, in fact. It would be just as easy to prove it from stools and cows as anything else. It’s really quite simple. Reversing the usual mathematical formula, it’s possible to reach the same results in reality by treating motion as a fixed point and stability as a form of motion. You were told that the earth goes round the sun and the moon goes round the earth. Well, in my formula, we first treat it as if the sun went round the earth——�
She looked up radiantly. “I always thought it looked like that,� she said emphatically.
“And you will, of course, see for yourself,� he continued triumphantly, “that by the same logical inversion we must suppose the earth to be going round the moon.�
The radiant face showed a shadow of doubt and she said “Oh!�