The Siege of Syracuse by Dan Armstrong

Author:Dan Armstrong [Armstrong, Dan]
Language: eng
Format: epub
ISBN: 9780983004547
Publisher: Mud City Press
Published: 2017-05-28T04:00:00+00:00

That same week I completed the last of the six parabolic mirrors. They were small, not much larger than my open palms placed side by side. Archimedes had me assemble a round wooden scaffold, about the size of a shield, built from the pieces of wood Orestes had given me two weeks earlier.

I attached the six mirrors so that each could be adjusted, up or down, left or right, by two screws. Then I mounted the scaffold on a wooden tripod with a pivot so the entire array of mirrors could be turned and aimed.

I presented it to Archimedes in the early afternoon. He told me to place the array in the patch of sunlight coming through the south window, and to position it so that it reflected the sunlight onto the east wall. When I did this, six overlapping disks of light, each about the size of an apple, appeared on the stone wall.

Following Archimedes’ instructions, I fine-tuned the aim of each mirror with the screws until the six disks of light became just one bright circle.

“Now slowly draw the entire frame back, Timon, so that you make that circle of light as small as you can.”

I scooted the frame away from the wall, causing the circle to decrease in diameter. When the circle got very small, and I had made a few more minor adjustments to the individual mirrors, the wall began to steam. Archimedes told me to ease the frame back a little bit more, and to continue adjusting the mirrors, until the circle became a tiny dot. Archimedes knelt beside the wall and used a stick of wood to touch the dot of light. The stick burst into flame before I could count to three.

We exchanged a look. Archimedes was as impressed as I was. “Can you imagine what an array of fifty mirrors might do?” he asked.

I nodded my head in wonder.

“We are only just beginning, Timon, but we are learning how this works,” he said with unusual animation. “Come look at this.”

He went over to the abacus. He stood on one side of the workbench. I stood on the other. He dampened and smoothed the sand in the abacus, then used his wooden stylus to draw the cross section of a parabolic mirror—a simple curved line. “The work of Apollonius in Alexandria and Diocles in Arcadia,” he said, “provides the geometric basis for what we just saw.”

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