beast and the
silicon-monster were the strangest beings conceivable, but I was wrong.
These creatures are still more alien, less understandable than either
and far less comprehensible than Tweel, with whom friendship is
possible, and even, by patience and concentration, the exchange of
ideas.

"Well," he continued, "we left the dream-beast dying, dragging itself
back into its hole, and we moved toward the canal. There was a carpet of
that queer walking-grass scampering out of our way, and when we reached
the bank, there was a yellow trickle of water flowing. The mound city
I'd noticed from the rocket was a mile or so to the right and I was
curious enough to want to take a look at it.

"It had seemed deserted from my previous glimpse of it, and if any
creatures were lurking in it--well, Tweel and I were both armed. And by
the way, that crystal weapon of Tweel's was an interesting device; I
took a look at it after the dream-beast episode. It fired a little glass
splinter, poisoned, I suppose, and I guess it held at least a hundred of
'em to a load. The propellent was steam--just plain steam!"

"Shteam!" echoed Putz. "From vot come, shteam?"

"From water, of course! You could see the water through the transparent
handle and about a gill of another liquid, thick and yellowish. When
Tweel squeezed the handle--there was no trigger--a drop of water and a
drop of the yellow stuff squirted into the firing chamber, and the water
vaporized--pop!--like that. It's not so difficult; I think we could
develop the same principle. Concentrated sulphuric acid will heat water
almost to boiling, and so will quicklime, and there's potassium and
sodium--

"Of course, his weapon hadn't the range of mine, but it wasn't so bad in
this thin air, and it _did_ hold as many shots as a cowboy's gun in a
Western movie. It was effective, too, at least against Martian life; I
tried it out, aiming at one of the crazy plants, and darned if the plant
didn't wither up and fall apart! That's why I think the glass splinters
were poisoned.

"Anyway, we trudged along toward the mud-heap city and I began to wonder
whether the city builders dug the canals. I pointed to the city and then
at the canal, and Tweel said 'No--no--no!' and gestured toward the
south. I took it to mean that some other race had created the canal
system, perhaps Tweel's people. I don't know; maybe there's still
another intelligent race on the planet, or a dozen others. Mars is a
que