What was left on the floor
A trading day on the New York Stock Exchange ended as paper: order slips, notes and tape swept off the floor by hand. Every price of the day had passed through someone's fingers first.
MEN SWEEPING UP THE FLOOR OF THE STOCK EXCHANGE, NEW YORK, 1908 · Library of Congress, public domain (LCCN 2013646362) · photograph, toned to the page
Outside, on Broad Street, the curb market traded in the open air. Brokers stood in the road; clerks leaned from the windows above and signalled orders down to them by hand. A price discovered in one room had to cross a street before it existed anywhere else.
BROAD STREET AND CURB BROKERS, NEW YORK CITY, 1916 · Library of Congress, public domain (LCCN 97517304) · photograph, toned to the page. How humans solved this before today's machinery: they carried the price by hand and voice, and accepted that it arrived late.