Mescolare 3 volumi di acido cloridrico,/? 1,19 g/ml circa, con 1 volume di acido nitrico, ρ 1,40 g/ml circa. ###>Mix three volumes of hydrochloric acid, ρ 1.19 g/ml approxi­mately, with one volume of nitric acid, ρ 1.40 g/ml approxi­mately.