Aumento (1966) has stated that I “erroneously calculated” a value of 8.53 × 10-6 °C-1 for the linear coefficient of expansion of high cristobalite. This unfortunate remark carries with it a disparaging implication of arithmetical ineptitude. The figure is incorrect in the reference, Lukesh (1942), to be sure, but had Aumento quoted a correct value (one based on the data which were available and which he presumably correctly calculated) of 8.93 × lO-6, the high probability of a typographical error would have been quite obvious to the discerning reader. The reference cited was the abstract of a paper read by title only at the 1941 meeting of the Mineralogical Society of America held in Boston. Since pre-publication proofs of such abstracts are not provided to the authors, the error could not be noted and, hence, remained uncorrected.