Permanent Adjustment of Tilting Level

In case of tilting level, it is not essential that the vertical axis of the instrument should be truly vertical. Therefore, the first fundamental relation is not required to be satisfied.

The second fundamental relation is being tested and if necessary, adjusted as given in case of dumpy level.

The third fundamental relation is tested and if necessary, adjusted as given in case of dumpy level, with following modifications after Step 3.

Step 4: The tilting screw is used to bring the line of sight to intersect the distant staff at d'.

Step 5: The bubble is then brought to the centre by means of the capstan screws on the bubble tube.

Step 6: The test and adjustment is repeated till the bubble remains central when the staff reading is d'.

Note:

In case of a dumpy level, the line of sight is moved by adjusting the diaphragm but in case of tilting level bubble is centred by adjusting capstan screws on the bubble tube.

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