The plan of writing with rice-water, to be rendered visible by the application of iodine, was practised with great success in the correspondence during the war in Affghanistan. The first letter of this kind was received from Jellalabad, concealed in a quill. On opening it, a small paper was unfolded, on which appeared only a single word, "iodine." The magic liquid was applied, and an important dispatch from Sir Robert Sale stood forth.