QUESTION TWO $(20$ Marks$)$

a$)$ Describe the field procedure for the permanent adjustment of the level $($make use of necessary sketches for full marks$)(10$ Marks$)$

b$)$ The readings obtained from a two$-$peg test carried out on an automatic level with a staff placed on two pegs A and $B50m$ apart are:

With the level midway between A and $B$

Staff reading at $A=1\mathrm{.}283m$

Staff reading at $B=0\mathrm{.}860m$

With the level positioned $5m$ from peg $B$ on line $AB$ extended

Staff reading at $A=1\mathrm{.}612m$

Staff reading at $B=1\mathrm{.}219m$

Calculate the collimation error of the level per $20m$ sighting distance and the horizontal reading that should be observed on the staff at A with the level in position $5m$ from B$.(10$ Marks$)$