Heliograph - Definition
heliograph
n 1: an apparatus for sending telegraphic messages by using a
mirror to turn the sun's rays off and on
v 1: signal by means of a mirror and the using the sun's rays
n 1: an apparatus for sending telegraphic messages by using a
mirror to turn the sun's rays off and on
v 1: signal by means of a mirror and the using the sun's rays