Here is a nice post by Simon Johnson on what bank capital is and what it is not. Johnson is an advocate of higher capital requirements for banks. In my new book Banking in Crisis, bank capital plays a very important role in contributing to pre-1940 British banking stability and its absence played a major role in the 2008 financial crisis.
My colleague and former PhD student Gareth Campbell has created a website about the British Railway Mania - click here . This episode has been described by the Economist as probably the greatest bubble in human history. Gareth's website provides background on the Mania and posits some explanations for the 'bubble'. In his explanation of why the bubble happened, Gareth places a lot of emphasis on investor myopia regarding future dividends and uncalled capital. His study of investors during the episode does not support the view that this episode was fuelled by naive and irrational investors.