"During the last campaign against Geronimo in 1886, the U.S. Army introduced a heliograph system for the rapid transmission of messages across the Southwestern deserts.

The heliograph was a small, round mirror mounted on a movable bracket and a tripod. By catching the sun, it could flash coded signals great distances.

The British had pioneered military use of heliographs in India during the 1860s. When Gen. Nelson A. Miles was chasing Montana Indians in 1878, he had six of the devices and found them very effective. Upon his transfer to Arizona, he decided to use them there.

By the time Geronimo and his handful of warriors made their final raid, the telegraph had been strung from Tucson to El Paso.

The trouble was, the Apaches had learned to cut the wire and then false-splice it with rawhide, so that repair crews could not see the break from the ground."

Get the Story:
Marc Simmons: Trail Dust: Army used 'talking mirrors' to help track Geronimo (The Santa Fe New Mexican 2/23)