k it's highly unlikely that it will progress
in any such regular fashion. Instead, the front probably will increase
erratically, but in a kind of progression. It may double its frontage at
approximately regular periods."

Scotty scratched his chin. "Double its frontage, huh? What does that
mean?"

"Maybe four hundred square feet today, eight hundred tomorrow, and
sixteen hundred the day after. We won't know the rate of growth, or the
time scale, until we've watched it for a while. But I talked with Balgos
and Hartson last night at some length, and their opinion is that we
probably have a couple of weeks, maybe even three or four. But not
months."

Rick whistled. "That fast? When will we be sure?"

Zircon shrugged. "Can't tell. We'll keep shooting on a daily schedule,
and perhaps in three or four days we'll see enough growth in the front
to make an estimate. But even that can be misleading. If the magma
strikes a softer area, it can grow even more rapidly. Our best bet will
be to keep a daily watch from now on."

Rick looked up at the extinct cone of El Viejo. In his imagination he
saw the top blow off in an earth-shaking explosion and millions of tons
of white-hot lava spurt high in the air. Then, when the lava came
down ...

"We'd better get on the ball," he said. "Almost time for our first
shot."

"Want to connect up?" Zircon asked.

"I guess so." Rick had never handled dynamite before, but there was no
time like the present to get started. He took sticks from his pocket,
then a cap. Zircon handed him the crimping tool. He put a cap in place;
then, with infinite care, put the crimping tool in position. He took a
deep breath and squeezed. Nothing happened, except that the cap was now
held tightly.

Rick let his breath out and grinned. Zircon and Scotty grinned back.

"When you get real salty," Scotty said, "you'll crimp the caps on with
your teeth."

"Ha!" Rick said. "And blow my head off?"

"It's possible," Zircon agreed. "It has happened. My advice is, don't
try it. I've seen men do it, but it always gives me the shudders. Come
on. Let's plant the charge and lay the wire."

The shots went off on schedule, and the party returned to the hotel.
Later, in analyzing the shots and making a new sketch, Jeffrey Williams
thought the magma front had grown slightly from the previous day, but
since the first tracings were gone, there was no way of being sure.

David Riddle and Brad Connel walked in as he finis