t the
matter. He even remembered to turn off his gadget because he would
need it to avenge Jill. But when he tried to think of any subject
unconnected with revenge, his mind became confused and agitated.

Two miles along the highway, which had not yet turned to head in
toward Boulder Lake, there was a farmhouse. Lockley walked heavily to
the abandoned building. He found the door locked. Without conscious
thought, he forced it. He searched the closets. He found a shotgun and
half a box of shells. He considered them, then left the gun and all
the shells but three. He went out. Presently he laid a shotgun shell
down on the road. He paced off twenty-five yards and dropped another.
He dropped a third twenty-five yards farther on, and then carefully
counted off three hundred feet. The car had been just about that far
away when the explosions came.

He turned on his device. Two of the three shells exploded smokily. The
farthest away did not explode.

He did not rejoice. He went on without elation, but it became a part
of his painstaking search for vengeance that he knew he could set off
explosives within a hundred and twenty-five yards of himself. There
was something about the device he'd constructed which made explosives
detonate, up to a distance of a little over one hundred yards. He felt
no curiosity about it, though it was simple enough. The heterodyning
of extremely saw-toothed waves produced peaks of energy until the
saw-teeth began to smooth out. There were infinitesimal spots in
which, for infinitesimal lengths of time, energy conditions comparable
to sparks existed. This had not been worked out in advance, but the
reason was clear.

He came to the place where the main highway to Boulder Lake branched
off from the road he was following. He turned into it, walking
doggedly.

Three miles toward the lake, an engine sounded from behind him. He got
off the highway and turned the switch. A half-ton truck came trundling
openly along the road. It came closer and closer.

Small-arm ammunition exploded. The engine stopped and the light truck
toppled over onto its side. Lockley did not approach it. Its driver
might not be dead, and he would not find it possible to leave any man
alive who was associated with Jill's captors. He passed the truck and
went on up the highway.

Seven miles up the road a truck came down from Boulder Lake. Lockley
placed himself discreetly out of sight. He turned on his instrument. A
gun flew t