A level is set up midway between two wood stakes that are about 300 ft apart. The rod reading on stake A is 8.72 ft and it is 5.61 ft on stake B. The level is then moved to point B and set up so that the eyepiece end of the telescope is just touching the rod as it is held plumb on the stake. A reading of 5.42 ft is taken on the rod at B by sighting backward through the telescope. The level is then sighted on the rod held on stake A, where a reading of 8.57 ft is noted.
(a) What is the correct difference in elevation between the tops of stakes A and B?
(b) If the level had been in perfect adjustment, what reading would have been observed at A from the second setup?
(c) What is the line-of-sight error in 300?
(d) Describe how you would eliminate the line-of-sight error from the telescope.