I have read it, yes. I found it sort of unsatisfying-- but yes, he had a remarkable grasp of technology's capacity. You're rather widely read, aren't you-- that's a bit of an obscure Twain gem.

Yes, they gave me a little trouble initially and they're not terribly strong, but they are magnets, at least.

Well.... yes and no. There's only so many possible configurations that exist for elements, and iron, as a for-instance, is common on asteroids in our system, and logically should be common on asteroids out of our system too. 'There's only so many ways to make rock,' I suppose I should say. New alloys and compounds are quite likely, but I'd be surprised to find too many actual completely unknown elements here.... Still, anything is possible. But our hosts seemed to favor non-metallic construction materials. I think.

Mmm, yes, it's a little like hydrotherapy when it's light. Alas.