$1\mathrm{.}2$ A baseline for setting out a new plant on a mine was measured in two stages with

a $60$ metres steel tape with a tape mass of $1,0kg.$ The taping was done in

catenary supported only at the ends. A spring balance was used to apply the

correct pull $(70$N$)$ as specified on the tape.

The temperature was taken for every tape measurement and elevation differences

between the beginning and end of each measured length was determined by

levelling.

The tape was standardised by the manufacturer at $20C$ with the coefficient of

expansion at $0,0000119$ per $1C.$

The surface elevation is approximately $1610$ metres above mean sea level.

$($Radius of earth $=6377513$ metres$)$

Correct each measured length for slope, catenary and temperature and give the

horizontal distance of the base line reduced to mean sea level.