Page:Carroll - Euclid and His Modern Rivals.djvu/110

72 Nie. (innocently) What other Definition?

Min. No evasions, Sir! Read it at once! You know the one I mean.

Nie. (desperately) It's only this—'A surface is the path of a moving curve.' (p. 9.) Merely another way of looking at it, you know.

Min. (contemptuously) Oh! Merely another way of looking at it, is it? Of course the curve preserves its shape as it moves?

Nie. No doubt.

Min. Now look here. Take this Jargonelle pear—

Nie. Thank you very much. It is rather dry work—

Min. Stop! Don't eat it yet! Look at it. Would you call its curvature regular?

Nie. Certainly not: it bulges here and there, in all sorts of queer ways.

Min. Well, now take this bit of wire: bend it into any curve you like, and then move it so that its path may coincide with the surface of the pear.

Nie. (uneasily) I cannot do it.

Min. Well, eat it, then. That is possible, at all events. So! We start with a Definition which is simply ridiculous! Now for the distinction between 'right Line' and 'curve'—

Nie. Here my client's meaning is not very clear. The first Definition I can find is that of a curve. He says (p. 6) 'a point may be moved, and then it will describe a path. This path of a moving point is a curve.'

Min. Surely he does not mean that a point can never move straight? He must mean that there are two kinds