Nobili's rings \No"bi*li's rings\ [After Leopoldo Nobili, an
Italian physicist who first described them in 1826.]
(Physics)
Colored rings formed upon a metal plate by the electrolytic
disposition of copper, lead peroxide, etc. They may be
produced by touching with a pointed zinc rod a silver plate
on which is a solution of copper sulphate.
[Webster 1913 Suppl.]