Abstract: A method of measuring the deviation of the run of the actual vertical center axis of fluid filled bore holes and trenches relative to the direction of the design center axis thereof which bore holes and trenches are excavated under bentonite slurry comprises inserting into said bore holes and trenches a gauge means suspended from a cable means, whereby said gauge means is arrested inside said bore hole at any desired level, and thereafter a measuring cable means is connected to said gauge means and substantially tensioned and brought to run in an exact vertical direction whereupon above ground level the horizontal deviation of said cable means from the design center line of said bore hole or said trench is measured.