Measuring Tilt with an Automatic Level

摘要

The long-term or short-term tilt of structures such as locks or dams may be measured with an automatic level which has been temporarily modified for the purpose. The modifications consist of the addition of an autocollimating eye-piece and an optical vernier. A calibration mirror is also required for the measurement of long-term tilt. Accuracies of 1 to 5 seconds of tilt may be obtained. (Author)