VITRIOL, a name given to sulphuric acid and to certain sul phates. Oil of vitriol is concentrated sulphuric acid, C.O.V. and B.O.V. being abbreviations for "commercial" and "brown" oil of vitriol, respectively. Blue or Roman vitriol is copper sulphate; green vitriol, ferrous sulphate (copperas) ; white vitriol, zinc sul phate ; and vitriol of Mars is a basic iron sulphate.