In a note published in the June 1960 JOURNAL, 1 pointed out certain deficiencies in the initial strain concept introduced by Messrs. J. H. Arygris and S. Kelsey. In the August JOURNAL, those authors have disputed my conclusions with an argument which, I feel, does not pay due regard to current literature and I believe may be based on a misinterpretation of certain algebraic manipulations contained in my note. For they concluded that my note contained misprints, which it, in fact, did not. Due to these unfortunate circumstances Messrs. Argyris and Kelsey failed to illuminate the basic disagreement between our two formulations. For this reason I should like to set out in simple detail the exact nature of our disagreement and to point out, as clearly as possible, where the initial strain concept as developed by Messrs. Argyris and Kelsey becomes, I believe, somewhat inadequate and how the concept of fictitious thermal loads achieves greater validity.