Dr. Ericson holds firm to his beliefs that the valve was not invented as "a mere crook changing device." Dr. Ericson embraces the idea that the "co-inventors of the valve clearly intended to perfect the brass instruments by making them chromatic." I can't guarantee that you will jump on the bandwagon when you finish reading this article, but Dr. Ericson does thoroughly cover his topic. He has also included an illustration of Stoelzel valves and how they operate.(Good report material). Site by Arizona State University.