Discussion on “the effect of displaced magnetic pulsations on the hysteresis loss of sheet steel” (Chubb and Spooner) and “the unsymmetrical hysteresis loop” (Ball), St. Louis, Mo., October 20, 1915. (see proceedings for October, 1915)

M. G. Lloyd: One interesting thing about this work is the methods of measurement which have been used. It seems to me the methods used by the first authors, at least the principal method used, that involving the volt-second-meter which, I think, is what is usually called a flux meter, is applicable only to specimens with very large cross-sections, such as the cores of transformers or other large pieces of apparatus. I should think with a small specimen it would not be feasible to take such readings as are described. Measurements on an apparatus of that kind are always valuable with the object of applying the results to other similar apparatus. I always feel they are not of much value when getting the constants of the material, determining a physical law, or determining exponents, for the reason that there is a very nonuniform distribution of the flux. The flux-density varies considerably over the area of the material being tested, and that fact is likely to vitiate the results so far as determining the constant of the material is concerned. On that account I think it preferable to make use of test specimens for that particular purpose, as has been done in the other paper.