Today in 1981, US Patent 4253878 A was issued, an invention of Robert L. Weaver and Alastair M. Jamieson, assigned to The Molson Companies Limited, for their “Light Protective Bottle Glass.” Here’s the Abstract:

A light protective bottle glass for use in beer bottles to prevent or reduce flavor deterioration by exposure to light is prepared by adding 0.065 percent by weight of nickel oxide to the Ultraviolet Absorbing Green glass usually used in green beer bottles.