79 innovations

Invisible ink

Fulfilling many a childhood fantasy, Invisible Inkis for amateur spies and sleuths or just for those looking for a mediumthat's a little less permanent. Clear and invisible when applied topaper, the water-based ink turns blue when exposed to heat (like alight bulb) and disappears again when it cools. Packaged in anold-fashioned ink bottle, it also requires old-fashioned implements (anib, glass or quill pen).

Source: lshop.stores.yahoo.netAdded: 5 June 2007