How do banks use deposits to fuel economic growth and generate a profit for themselves?

First of all let me state the simple fact that when you deposit money in a bank the bank does not put the money into a safe deposit vault. It invests your money in many different forms of credit-bonds, commercial paper, mortgages and many other kinds of loans. In other Words, the bank puts your money to work to keep the wheels of industry and of agriculture turning around. A comparatively small part of the money you put into the bank is kept in currency - an amount which in normal times is wholly sufficient to cover the cash needs of the average citizen....