Key points are not available for this paper at this time.
Methods 361 1. Methods of measuring the resistance 361 (a) The galvanometer method 362 (b) The electrometer method 364 2. Methods of preparing the specimens 366 III. Volume resistivity 363 1. Effect of humidity 368 2 Effect of voltage 370 3. Effect of temperature 372 4. Effect of dielectric absorption 373 5. Values of the volume resistivity 375 IV. Surface leakage 378 1. Effect of humidity 380 2. Effect of temperature 399 3. Effect of exposure to light 400 (a) Effect of sunlight 401 (1) Deterioration of hard rubber 401 (2) Renovation of the surface of hard rubber 403 (3) Deterioration of other materials 403 (6) Effect of ultra-violet light 404 4. Nature of surface leakage 409 5. Methods of computing surface resistivity 411 V.
H. L. Curtis (1915) studied this question.