摘要 |
A time-lapse indicator in which a receptacle contains a fluid material having numerous discrete particles dispersed in a liquid carrier, and a layer of absorbent material in close proximity to the receptacle, the receptacle and absorbent material being separated from one another by a wall which is broken when the time period is to be determined by the indicator. The indicator normally has a pair of electrodes for measuring the resistance of the fluid material after a portion of the liquid carrier has been absorbed therefrom in the absorbent material. Mechanisms for both activating and reading the indicator may be used.
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