ite plain behind it.

I have spoken of the down-grade of this land here, culminating in the
depression which marked this part of the wall. It was that depression
which gave me my idea. Our heat-ray cylinders had so far been useless.
They had a range of only two hundred feet, and no power to attack a
barrage. Some of them had futilely been used; the snow and ice on the
ground above our recent fighting was melted in patches--pools of boiling
water lay on the naked rock; and the water, flowing down the depression,
had reached the ice-wall--a tiny stream of it, eating into the wall,
slowly, surely....

With my men I flew up the slope. The ice and snow here melted under
the close-range play of our heat-cylinders. Rivulets of boiling water
began creeping toward the city. Other men at my call joined us. Two
hundred of us soon were melting the ice. The rivulets merged into
brooks, to streams--and soon a river torrent of hissing, boiling water
gathering volume as it went, was surging at the wall. The wall
began melting--itself feeding this monster which was eating at its
vitals ... a yawning hole began opening at the base of the wall ... it
began sagging at the top ... crumbling....

The segment of barrage here went dark. No trickery now; the barrage at
this point actually was broken. The boiling river went through the wall,
swept down the slope into the city. Through the great clouds of steam I
could see the Ice Palace with its brittle outlines softening under the
heat ... one of its thin spires broke off and fell....

Feverishly we added to the river source. The whole area here was grey
with steam. Girls had joined us ... Elza was not among them ... Elza!
With my triumph there lay always in the background of my consciousness
the weight of my fear for Elza....

The fighting in the other sector had continued desperately. Our power
house was hopelessly damaged; the towers, with their power gone, were
using their batteries; soon they would be exhausted. But now we
abandoned that sector; our remaining towers--all our flying forces--came
to this melting area where the vanishing city lay defenseless before
us.... We hurled ourselves into it, using only our heat-rays. Everywhere
we added to the boiling torrent; even the interference heat of the
fighting was to our advantage. This brittle city which owed its very
existence to the congealing cold, lay enveloped in a cloud of steam.

Then Tarrano played his last card. The cubical b