77° N

23° S

13° E

13° W

(i) and (iii)

(i) and (iv)

(ii) and (iii)

(ii) and (iv)

cross staff

level

chain

prismatic compass

(i), (iii), (ii)

(i), (ii), (iii)

(ii), (iii), (i)

(iii), (i), (ii)

tightening the capstan-headed nuts of level tube

measurement of horizontal angles only

measurement of vertical angles only

measurement of both horizontal and vertical angles