Tests on oil-impregnated paper — IV: Mechanism of breakdown

IN three previous papers^1,2,3 we have presented some of the results of our studies on miniature cable specimens started in 1934. In the first two papers the relative life histories and the results of post-mortem examinations were given for (a) specimens saturated with gas at one atmosphere pressure, (b) specimens saturated with gas at 200 pounds per square inch pressure, and (c) specimens, gas free but under one atmosphere liquid pressure. In the third paper we presented data on fluid flow through cable paper and showed that even with high-viscosity impregnants and low-permeability papers there was sufficient flow through our specimens to prevent void formation.