It was recalled that theoretical estimates of this stress exhibited an exponential dependence upon the ratio of the spacing between glide planes and the unit slip distance. The present author had previously corrected an error of a factor of 2 in this exponent in Peierls’ original analysis. A revised published estimate had then introduced a further factor of 2. Three experimental estimates were available which had been deduced from Bordoni peaks (and agreed with the above revised theory), from the flow stress at low temperatures (which agreed with the Peierls-Nabarro theory) and from the rate of Harper-Dorn creep (which agreed with the Peierls-Nabarro theory). Since the revised theory above was much better founded than was the Peierls-Nabarro theory, the agreement of 2 experimental results with the latter theory was judged to be unexpected. The discrepancy was resolved by using more recent results.

Theoretical and Experimental Estimates of the Peierls Stress. F.R.N.Nabarro: Philosophical Magazine A, 1997, 75[3], 703-11