EXPERIMENT ON THE PRECISION OF ENGINEERING LEVELS.

Five engineering levels of different design were compared for precision in measuring heights of thirty-six pegs. Each instrument was used to measure the reduced levels of the pegs several times and the grand-pooled root-mean-square error values for all pegs were computed. The results obtained show that there is little difference in the precision of the test instruments in measuring heights. It is believed that, for many engineering projects, any of these instruments can be used without much affecting the overall required accuracy of the survey.