Permanent adjustment of theodolite, whataate the fundamental lines of transit theodolite, state different relationship between fundamental lines of theodolite.

Following are fundamental lines of transit theodolite:-

1. Vertical axis
2. Horizontal axis
3. Line of collimation or line of sight
4. Axis of plate level
5. Axis of altitude level
6. Axis of the striding level, if provided. 

Desired relation should exist between these lines:-

1. The axis of plate level must be in a plane perpendicular to the vertical axis. 
2. The line of collimation must be perpendicular to the horizontal axis at its intersection with the vertical axis. 
3. The horizontal axis must be perpendicular to the vertical axis. 
4. The axis of altitude level must be parallel to the line of collimation. 
5. The vertical circle vernier must read zero when the line of collimation is horizontal.