Invisible Gold Ink

Put as much gold in as small a quantity of aqua regia as will dissolve

it, and dilute it with two or three times the quantity of distilled


Next dissolve, in a separate vessel, fine pewter in aqua regia, and

when it is well impregnated, add an equal quantity of distilled water.

Write your characters with the first solution: let it dry in the

shade. To make them visible, draw a pencil or sponge, dipped in the

second solution, over the paper, and the characters will appear of a

purple colour.

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