"TRYING OUT" THE GRIDLEY BOYS The chainmen picked up the transits, carrying also the chains and rods.

Rutter led the way, Tom and Harry keeping on either side of him, except when the rough mountain trail narrowed.

Then they were obliged to walk at his heels.
"We are making this survey first," Rutter explained, "and then the leveling over the same ground follows within a few days.
Both the surveying and the leveling have to be done with great care.

They must tally accurately, or the work will all go wrong, and the contractors would be thrown out so badly that they'd hardly know where they stood.

A serious mistake in surveying or leveling at any point might throw the work down for some days.