"How does it cock?" Ian asked. There was a steel claw arrangement hooked to the center of the wire string stretched across the shallow cord of the bow. He pulled at the string with a tentative hand. It was like a solid bar, immovable.
"That's a stiff draw," he said.
"Over three hundred and fifty pounds," the machinist said. "Brace the stock against your hip and hold the grip. Now put your other hand on the forestock, through that oval metal loop that sticks out beyond the wood. Feel that catch under your thumb? Press it down."
Ian obeyed. A steel lever came out of its slot in the forestock, hinged at the rear a few inches ahead of the trigger guard.
"Pump it back and forth, like the lever on a car jack."
There was a soft heavy resistance with every stroke, and the crossbow's string inched backward. At the sixth it clicked home near the trigger action and the rear sight, the heavy steel bow bent and ready.
S.M. Stirling, Island in the Sea of Time (63-64)