The static and the impulse breakdown of paraffin oil and xylol were investigated by means of the electro‐optical shutter. To obtain satisfactory operation of the shutter it was found necessary to use a double shutter consisting of three crossed nicol prisms and two Kerr cells. Because of the liquids being only commercially pure and of the occluded air and moisture, several types of sparks were observed for a given method of applying the voltage. For the early stages of static breakdown, however, the ionization was usually more intense at the anode. With impulse breakdown in paraffin oil there was observed no increase in uniformity of type of breakdown as compared to static breakdown. With xylol, on the other hand, a fair degree of uniformity in type was observed. This uniformity was due to the extremely short time of voltage application, thus causing a decrease in the secondary effects resulting from impurities and occluded gasses.