heliograph

A major renovation of the Ransom Center in 2003 created more than 40,000 square feet of public space and a gallery with permanent exhibits of some materials, including a Gutenberg Bible and the Niépce Heliograph, the world’s oldest known surviving photograph.

Here, in 13,000 square feet, is a 16th-century copy of the first published book on cryptology, Johannes Trithemius’s “Polygraphiae,” along with a cipher disc used by the Confederacy during the Civil War; children’s school notebooks used by the Vietcong to cloak intelligence on fighting forces; and a heliograph, whose maneuverable mirrors were used in the First World War to flash sunbeams in Morse Code patterns.

To this shot the heliograph flashed a cordial expression of approval.

Far in rear, upon a hill-top, a heliograph blinked and flickered in the sun.

Leaving Bill to recover the trail, he hastened back to heliograph that the safari might advance, and by the time he had once more penetrated the wood and rejoined the Wanderobbo, Ferrier had come within sight in a hollow a mile and a half to the east.