'I should say it is a sea-urchin.'

'Exactly!' he cried, with an air of exaggerated surprise, as when an infant has done something clever. 'It is a sea-urchin – a common echinus. Nature repeats itself in many forms regardless of the size. This echinus is a model, a prototype, of the world. You perceive that it is roughly circular, but flattened at the poles. Let us then regard the world as a huge echinus. What are your objections?'

My chief objection was that the thing was too absurd for argument, but I did not dare to say so. I fished around for some less sweeping assertion.

'A living creature needs food,' I said. 'Where could the world sustain its huge bulk?'

'An excellent point-excellent!' said the Professor, with a huge air of patronage. 'You have a quick eye for the obvious, though you are slow in realizing the more subtle implications. How does the world get nourishment? Again we turn to our little friend the echinus. The water which surrounds it flows through the tubes of this small creature and provides its nutrition.'

'Then you think that the water-'

'No, sir. The ether. The earth browses upon a circular path in the fields of space, and as it moves the ether is continually pouring through it and providing its vitality. Quite a flock of other little world-echini are doing the same thing, Venus, Mars, and the rest, each with its own field for grazing.'

The man was clearly mad, but there was no arguing with him. He accepted my silence as agreement and smiled at me in most beneficent fashion.

'We are coming on, I perceive,' said he. 'Light is beginning to break in. A little dazzling at first, no doubt, but we will soon get used to it. Pray give me your attention while I found one or two more observations upon this little creature in my hand.

'We will suppose that on this outer hard rind there were certain infinitely small insects which crawled upon the surface. Would the echinus ever be aware of their existence?'