Pre-1900 formula for making black ink: "Take 2 ounces Extract Logwood, 1 gallon soft water, boil slightly or simmer in an iron vessel 15 minutes; dissolve in a little hot water, 24 grains bichromate of potash, 12 grains prussiata potash, and stir into the liquid a few minutes while over the fire. Take off and when settled, strain it twice through common muslin or sheeting cloth. The above ink is jet black from the first, flows beautifully from the pen and also indellible that even oxalic acid will not remove it from paper." Edna Clack