Using a reproducible pulsed voltage technique, the electric strengths of liquid hexane, heptane, and tetradecane have been measured with small electrode spacings (approximately 2 to 200 microns). The electric strengths are found to change inversely with the logarithm of the separation in accord with theoretical expectation. On the basis of an approximate model of the breakdown process, the measurements on heptane yield values of 9×10−7cm for the electron mean free path in the liquid and 9 for the number of multiplications per electron required for breakdown.