This chapter looks at the development of electric lighting and power supply networks in terms of the battles waged around 1887-1892 between proponents of direct and alternative current systems of electrical supply in order to raise questions about technical progress as a continuous flow. Utilizing the physics concept of hysteresis as the persistence of an altered state when the force that caused alteration ceases, the chapter concentrates on the critical moments or ‘points of bifurcation’ in the dynamic of technical change that are prone to appear at the early stages of an incremental process. The chapter concludes from its reading of the ultimate victory of alternative over direct currents of electrical supply that innovation implies not so much the work of unique creative attitudes in the manner of the classic Schumpeterian entrepreneur, as it does the occupation of a pivotal situation during comparatively brief moments of industrial development when the balance between choices can go either way.