overharden - Weblio 英和・和英辞典 (original) (raw)

• 1661, Robert Boyle, “[Some Specimens of an Attempt to Make Chymical Experiments Useful to Illustrate the Notions of the Corpuscular Philosophy.] The History of Fluidity and Firmnesse. The Second Part. Of Firmnesse.”, in Certain Physiological Essays and Other Tracts; […], 2nd edition, London: […] Henry Herringman […], published 1668, →OCLC, page 286:
  [I]t has acquir'd ſuch a hardneſs, that being throvvn againſt the floor it vvould rebound, and vvas brittle like over-harden'd Steel.
  An adjective use.