What happened to depositors in the 1920s when a bank failed?

As the economic depression deepened in the early 30s, and as farmers had less and less money to spend in town, banks began to fail at alarming rates. During the 20s, there was an average of 70 banks failing each year nationally. After the crash during the first 10 months of 1930, 744 banks failed – 10 times as many. In all, 9,000 banks failed during the decade of the 30s. It's estimated that 4,000 banks failed during the one year of 1933 alone. By 1933, depositors saw $140 billion disappear through bank failures.

necessary and proper clause. the congress shall have power to all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this constitution in the government of the united states, or in any department or officer thereof.