| 摘要 |
In an indicator for visually displaying extremely small displacements between two points within a structure, a change of color visible through an indicator window (26) occurs during a preselected portion of a predetermined displacement within the structure. The color change occurs due to an increase in thickness of a lightabsorbing fluid (42) in the central area of a clear, flexible indicator means separating a colored portion from the indicator window. Substantially no light-absorbing fluid is permitted to enter the central area until a preselected displacement has occurred since the colored portion is firmly, resiliently biased against the indicator window until that amount of displacement has occurred. Thereafter, light-absorbing fluid is permitted to enter the central area. This device concentrates visual indications of displacements into limited segments of an overall displacement,
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