Problems were discussed which arise in the development of electrochemi
cal coulometers used as timers having a dissolving metal anode as the
element defining time elapsed. This time is counted in terms of dissol
ution of a cylindrical metal rod following Faraday's law. Attention is
focused on electrochemical dissolution of the end of a rod with insul
ating walls, on the influence of electrode size, natural convection, e
lectrolyte composition, and temperature.