Was surprised to see that some hams here had learned Morse from Boy Scout flashlights. That seems very difficult to me.
Anyway, was reading about early communication by light... heliographs (reflected sunlight) and signal lamps. http://en.wikipedia.org/wiki/Heliograph
"The distance that heliograph signals could be seen depended on the clarity of the sky and the size of the mirrors used. A clear line of sight was required, and since the earth's surface is curved, the highest convenient points were used. Under ordinary conditions, a flash could be seen 30 miles (48 km) with the naked eye, and much farther with a telescope. The maximum range was considered to be 10 miles for each inch of mirror diameter. Mirrors ranged from 1.5 inches to 12 inches or more. The record distance was established by a detachment of U.S. signal sergeants by the inter-operation of stations on Mount Ellen, Utah, and Mount Uncompahgre, Colorado, 183 miles (295 km) apart on Sept 17, 1894, with Signal Corps heliographs carrying mirrors only 8 inches square.
And isn't this interesting of signal lamps (like those used on war ships):
"Although it was originally thought that it was only possible to communicate by line-of-sight, in practice it was possible to illuminate cloud bases both during the night and day which allowed for communication beyond the horizon."http://en.wikipedia.org/wiki/Signal_lamp