For one thing, said Douglas, who worked in Sollas' laboratory, the telltale 1953 analysis of the skull showed it had been aged with the chemical potassium bichromate.
The slogan was Lucky's way of saying that there would no longer be enough chrome green ( a derivative of bichromate) to make green ink.
Such exhaled gasses he made to pass through a solution of potassium bichromate, which changed from yellow to green in proportion to the amount of alcohol on the individual's .