[ProtectOurFreedom]

Platforms at the top of the towers would have held burning braziers to act as beacons.

Those Romans sure had odd ways to make a signal fire...

[gleeaikin]

Is there any sign that reflective or optical surfaces and objects were used to increase light transmission? Romans had glass, but did they ever discover silver surfacing to create mirrors? Also did they ever use prisms or other cut glass for any purpose?

[MikelTackNailer]

Burning braziers...good one! Let loose the lions - give the people what they want.

Where it said "The views from the topmost stage of the pharos seem to have been deliberately angled so that it could communicate not only with the second lighthouse on Western Heights but with Cap Gris Nez on the French coast" shows that J.R.R. Tolkien didn't dream up the concept of relayed signal towers all by himself.

Then there's the lost Lighthouse (Pharos) of Alexandria, one of the Seven Wonders of the Ancient World (which stood for over 1000 years before earthquakes had their way.

You can see they kept the same basic design stressing function over style. The English one stood around 40 feet while Alexandria's was 330, hence the emphasis on a massive base.