Joseph Jaggers

Joseph Hobson Jaggers (1830–1892) was a British engineer, referred to as, but not an exclusive holder of the title of, the man who broke the bank at Monte Carlo.

Jaggers gained his practical experience of mechanics working in Yorkshire's cotton manufacturing industry. He extended his experience to the behaviour of a roulette wheel, speculating that its outcomes were not purely random numbers but that mechanical imbalances might result in biases towards particular outcomes.

In 1873, Jaggers hired six clerks clandestinely to record the outcomes of the six roulette wheels at the Beaux-Arts Casino at Monte Carlo, Monaco. He discovered that one of the six wheels showed a clear bias, in that nine of the numbers (7, 8, 9, 17, 18, 19, 22, 28 and 29) occurred more frequently than the others. Exploiting this characteristic, Jagger swept through his first day earning USD 70,000. Over the next three days, Jaggers amassed $300,000 in earnings with other gamblers in tow emulating his bets. In response the casino rearranged the wheels, which threw Jagger into confusion. After a losing streak, Jaggers finally recalled that a scratch he noted on the biased wheel wasn't present. Looking for this telltale mark, Jaggers was able to relocate his preferred wheel and resumed winning. Counterattacking again, the casino moved the frets, metal dividers between numbers, around daily. Over two days Jaggers would lose, giving up, he took his remaining earnings, USD 325,000, and left Monte Carlo never to return.

In 1892, Fred Gilbert wrote a popular song, The Man Who Broke the Bank at Monte Carlo that is mistakenly attributed to Jaggers' exploits. Instead, the song is a celebration of Charles Wells, another Englishman, who in 1891 won handsomely in Monte Carlo.