Steam locomotive et optical telegraph : ce qu'ils ont en commun

1. Étape 1. Steam locomotive — utilise — Railway track. It runs on rails.
2. Étape 2. Railway track — a inspiré — Time zones. Introduced because of railway timetables.
3. Étape 3. Time zones — utilise — Electrical telegraph. Synchronizing time by telegraph.
4. Étape 4. Electrical telegraph — a évolué de — Optical telegraph. The electrical telegraph replaced semaphore lines.

Ouvrir Evothings