Labels:text | book | paper | handwriting | paper product | publication | document OCR: formular q Secret Saks 3. Alum ink can be made of a 1% 1. a solution of Chloride of Cobalt , although solution of alum (Htyplic pencil showings) it does wor make an entirely invisible the message can be developed with mik , is so pale that no unsuspecting heat - such as a hor cion or a eye would notice it on paper , When cigarette hela underneath the paper. this paper written on is heated, the letters 4. Lead Acetate ink is muy porsinous will appear greenish in colom but (sugar of lead ) . lire 1/5% solution quite clear. Heis lik has the advantage Hi Chemical used for removing that the moment the paper in cold ? domestic paint from the hands , and again, the mess ap disappears, and a clean pour nit. Develop with a this process can be repeated as often small amount of depilatory ( Veel an is necessary. for removing har) and white vinegar 2. Phenolphthalein Juk (Pungen Tablets) or any acid . is made in the following manner. A solution 5. Agua Fortis is made in the proportions of 1/2% ( about half a tablet to a coffee - of 1 part of aqua fortin to 3 pauly spoonful of stringent ammonia ) aus 2 gratis. His ink is developed by or 3 tablespoon ful of cold water, thai damping the paper, the message completes his recht ink . To develop. disappearing when the paper dis. wake a very strong solution gwashing 6. Ammonia aik is made from domestic soda (to saluation point), and Ammonia and soil remain invisible place the paper in the solution until until it is heated. tu message appears .
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