In the mid 1800s, a stock price traveled only as fast as a runner could carry a slip of paper down Wall Street. Traders in Philadelphia or Boston made do with a single summary once the trading day had closed, which meant acting on prices that had already expired. Then Edward A. Calahan of the American Telegraph Company put stock quotes on a dedicated telegraph wire, unveiling his system in New York City on November 15, 1867. Its steady clicking gave the machine its name: the ticker.

This episode follows the ticker from fragile hand cranked printing telegraphs to Thomas Edison’s 1869 universal stock ticker, which printed letters and numbers directly and removed the need for a Morse code operator. It explains the 32 symbol wheel that limited the machine to about one character per second, the monopoly the exchange built to keep every subscriber on the same tape, and the afterlife of all that paper in ballparks, woven art, and the parades of lower Manhattan.

• Calahan, who invented the first stock price telegraph system in 1863, later founded the security company now known as ADT.
• By 1883 the transmitter keyboards at the exchange looked like a piano, with black keys for letters and white keys for numbers and fractions.
• In 1890 exchange members formed the New York Quotation Company and bought up competing ticker firms so that all subscribers received price and volume at the same moment.
• Stadiums installed tickers to receive out of town baseball scores, and weaver Dorothy Liebes worked used ticker tape into her art textiles.
• By the 1930s the tape ran 15 to 20 minutes behind the floor on heavy trading days, and the machines were obsolete by the 1960s. Today’s ticker tape parades mostly use shredded office paper.