The term slot machine (short for nickel-in-the-slot machine) was originally also used for automatic vending machines but in the 20th ⚽️ century came to refer almost exclusively to gambling devices. The first coin-operated gambling devices in the United States date to ⚽️ the 1880s, although they were actually mere novelties—such as two toy horses that would race after a coin was inserted ⚽️ in the machine—rather than direct gambling machines. Set on a bar in a saloon or similar establishment, such devices attracted ⚽️ wagering between patrons. With most machines, however, the proprietor paid off winning customers in drinks or cigars or sometimes in ⚽️ the form of trade checks (specially minted metal tokens) that could be exchanged for refreshments. By 1888 machines that paid ⚽️ off in coins were in existence. In the first ones, inserted coins fell onto an internal balance scale, where they ⚽️ might cause it to tip and spill other coins out; among later devices were ones with a circular display and ⚽️ a spinning indicator that came to rest on or pointed to a number, a colour, or a picture.

The first slot ⚽️ machines in the modern sense were invented by Bavarian-born American inventor Charles August Fey, at the time a mechanic in ⚽️ San Francisco, who built his first coin-operated gambling machine in 1894. The following year Fey built the 4-11-44 in his ⚽️ basement; it proved so successful at a local saloon that he soon quit his job and opened a factory to ⚽️ produce more units. In 1898 Fey built the Card Bell, the first three-reel slot machine with automatic cash payouts. The ⚽️ Card Bell had a handle that set the reels in motion when it was pushed down and playing card suitmarks ⚽️ that lined up to form poker hands. His next slot machine, the Liberty Bell, was built in 1899 and used ⚽️ horseshoes and bells as well as playing card suitmarks on the reels. Three bells lined up in a row meant ⚽️ the top payout. Chiefly because of the 1906 San Francisco earthquake, only 4 of more than 100 Liberty Bell machines ⚽️ built by Fey survive. The Liberty Bell proved immensely popular among saloon patrons in San Francisco and was quickly copied ⚽️ by Fey’s competitors, such as the Mills Novelty Company of Chicago.

Forces of morality and the clergy, and then of law, ⚽️ frequently opposed the operation of slot machines. By the time San Francisco banned them in 1909, there were some 3,300 ⚽️ slot machines in the city. In order to circumvent the law, Fey and his competitors built machines with no coin ⚽️ slots in which purchase and payout (perhaps in drinks and cigars) occurred surreptitiously across a saloon counter. Soon most slot-machine ⚽️ factories relocated, especially to Chicago.

The ubiquitous reel symbols of various fruits were first used in 1909 by the Industry Novelty ⚽️ Company. In an effort to circumvent legal restrictions on slot machines, the company called its machines chewing gum dispensers, replaced ⚽️ suitmarks on the reels with fruit symbols that suggested various flavours of chewing gum, and built a few machines that ⚽️ really did dispense gum. The idea was copied in the following year by the Mills Novelty Company, which added on ⚽️ their reels a picture of a chewing gum pack (soon stylized as the well-known “bar” symbol). The Mills Novelty Company ⚽️ also invented the “jackpot” in 1916, whereby certain combinations of symbols on the reels regurgitated all the coins in the ⚽️ machine.

During the 1920s the machines were popular throughout much of the United States, especially in resort areas, and they continued ⚽️ to be popular into the Great Depression years of the ’30s. But knowledge that the distribution of slot machines was ⚽️ often controlled by organized crime led to increasing legislation restricting their sale and transportation as well as their use except ⚽️ in private social clubs. Prohibition outside Nevada, which had relegalized gambling in 1931, was virtually total by 1951, although illegal ⚽️ operation, especially in private clubs, was widely ignored.