figure 1. A collection of oil and air circuit breakers, vintage 1900. (Image courtesy of the authors.) figure 2. A 40-kV breaker installed in 1901. (From R. Wilkins and E.A. Crellin, High Voltage Oil Circuit Breakers. New York: McGraw Hill, 1930.) 88 ieee power & energy magazine figure 3. An OCB from 1908 to 1958. (Used by permission of the authors.) may/june 2018