U. S. Government Standard Ink Recipe in Popular Science (January 1935, p. 54) 11.7 g tannic acid 3.8 g gallic acid 15 g iron sulfate 3 cc hydrochloric acid (aka muriatic acid; or 2 cc sulphuric acid) – used to prevent sediment forming 1 g carbolic acid-- a preservative to prevent mold* 3.5 g china-...