Historical Note on Recalescence

Abstract

IN the Presidential address referred to, I attempted to review the progress made in connection with iron and steel during the past century. I felt that, not with standing the very limited space at my disposal for recording the work of individuals, the name of Barrett must find a place, and I greatly regret that my friend considers the reference to him to be infelicitous. As regards the first point raised by him (to take the class of smith's work with which I have most experience), those who have to conduct the very delicate operation of hardening dies for coinage have long been familiar with what is now known, thanks to Prof. Barrett, as “recalescence” in cooling steel. Of course the artificers were ignorant of its true cause, and they usually describe the effect of the sudden glow in steel as being due to “the heat coming from inside the metal.” The fact that this industrial knowledge existed, does not in the least diminish the interest of Prof. Barrett's own observation (1873), nor lessen the vital importance of his work in showing that “Gore's phenomenon” (1869) is a reversible one. The relation of the work of Barrett to that of Gore was, moreover, indicated by me nearly ten years ago in the pages of NATURE (November 7, 1889, p. 16) as concisely as I could. In a recent number of NATURE (April 13, 1899, P. 567), a curve obtained by a method of my own is published, and it shows that there are no less than six points at which heat is evolved as iron cools down from 1150° C. to the ordinary temperature. I wish that Prof. Barrett, with his great experimental skill, had hastened the advance of our knowledge by continuing, during the past twenty-five years, investigations which would have led him to the discovery of the several very important points in carburised iron in which, as the metal cools, the evolution of heat cannot be detected by the unaided eye. I may add that I fully share with M. Osmond, with whom I have so long worked, his appreciation of the value of Prof. Barrett's investigation.