All of the insulators displayed here were designed by Ralph Mershon. He had some unusual theories about the behavior of electrical discharges when insulators flashed over and these theories were the basis for his tall long skirted insulator designs. His theories were later disproved as scientific and engineering research proved later that more squat insulators with an even distribution of thicker skirts fared better when they flashed over . Left to right: U-944, U-945("Mershon Type"), M-3890 ("Iroquois Type"), U-939b, M-3250 ("Shiwinigan Type")