Daniel. It's very hard for me to go on with these constant interruptions. Well, I was just saying there was a difference between a fan bellows and an ordinary bellows.

Mackenzie. Now, what is a fan bellows yourself, Mr. Murray?

Daniel (hopelessly). A fan bellows? Ah. Why now is it called a fan bellows?

Mackenzie (roughly). Don't be asking me my own questions.

Daniel (with a despairing effort). Well, now we will take it for granted it is because there must be something of the nature of a fan about a fan bellows. It is because there are fans inside the casing. And the handle being turned causes these—eh—fans to turn round too. And then the air comes out with a rush.

John. Aye. It must be the fans that pushes it out.

Daniel. Exactly. Well, now, the difficulty we find here is—(he pauses).

Andy. Aye.

John. Go on, Daniel.