| abstract |
A fusible colored substance (3) is housed in a hollow internal part of a protuberance (1), formed from a film capable of sagging under the application of an external pressure. The opening of the hollow part is hermetically sealed by a thin protection (9) also capable of sagging by application of said pressure. An absorbent (7), into which the meltable colored substance (3) can penetrate, when in the molten state, is arranged outside the thin shield (9) of the hollow part. A space, into which the holder falls when the shield (9) is broken by the application of pressure, is formed behind the shield (9). The carrier (5) serves to control the rate of penetration of the substance (3) into the absorbent (7) and, therefore, a stable permeation thereof into the absorbent (7). |