Take some white gum arabic, reduce it to an impalpable powder in a brass mortar, dissolve it in strong brandy, and add a little common water to render it more liquid, provide some gold in a shell, which must be detached in order to reduce it to a powder, when this is done moisten it with the gum solution, and stir the whole with a small hair brush, or your finger, then leave it for a night that the gold may be better dissolved. If the composition becomes dry during the night, dilute it with more gum water in which a little saffron has been infused, but take care that the gold solution be sufficiently liquid to flow freely in a pen; when the writing is dry polish it with a dry tooth. 46. WHITE INK FOR WRITING ON BLACK PAPER Having carefully washed some egg shells remove the internal skin and grind them on a piece of porphyry, then put the powder in a small vessel of pure water, and when it has settled at the bottom, draw off the water and dry the powder in the sun. This powder must be preserved in a bottle; when you want to use it put a small quantity of gum ammoniac into distilled vinegar, and leave it to dissolve during the night, next morning the solution will appear exceedingly white, and if you then strain it through a piece of linen cloth, and add to it the powder of egg shells in sufficient quantity, you will obtain a very white ink. 47. SECRET INK FOR YOUNG LADIES AND GENTS Take a drachm of clean rain water, put into it, in a clean vial, 10 or 12 drops of pure, clean sulphuric acid, and it is ready for use; write with this using a clean quill pen on letter paper, and when dry you can see no mark at all, then hold it to a strong heat and the writing becomes as black as jet. If you want to write to a young lady or gentleman, as the case may be, and fearing that the letter might be opened before she or he gets it, write with common black ink something of no importance, then between the lines write what you want to say with the secret ink. The person to whom you are writing must understand the scheme so that she or he may hold it to the heat and thereby make the writing visible. 48. CIDER WITHOUT APPLES