The machine works simply enough but at the time must have seemed like a marvel of machinery. If the customer wanted to deposit coins, the machine could tell what type of coins were being inserted (in the same way modern vending machines use the weight to tell the difference between coins). But customers depositing paper money had to actually set the slide dial on the machine to the amount they were depositing before telling the machine to stamp their bank books. We have to wonder how many people in the 30s tried to beat the system by tricking the machine into making their bank accounts look artificially flush.
posted by sooyup