San Francisco’s Telegraph Hill was so named because of the semaphore signal station erected on it in September 1847.
The station operated as an optical telegraph, having two hinged arms on a tall mast which were raised or lowered to relay information which could be read from downtown and the waterfront as to the type of ships entering the Golden Gate Strait and the cargo they might be carrying.
In gold-rush-era San Francisco it provided useful early information to merchants, traders and speculators as to the nature of the cargo arriving imminently at the city’s port so that the supply effect on prices of goods and commodities could be predicted.
