This chain was used to measure lengths accurately and reliably. The flat end off the “D” was laid on a known point and the surveyor stands on the chain. At the other end the survey assistant was directed towards a distant known point and the chain laid down. The chain was then ‘snacked’ to straighten it. The assistant pulled and lifted his end sending waves along the chain which straightened it. The “D” at the assistant’s end was then marked and the process repeated until the distant known point was reached.
To keep the chain in good condition it hand to be cleaned daily and oiled to prevent rust. The clean chain was folded into a ‘wheatsheaf’, wrapped in a rag and put into a leather chain-bag until needed again. The surveyors bag also contained a ‘slop corrector’. It was a piece of wood about an inch in section and six inches long. It has marked graduations for varying slopes and is a much more rare item to find as it rotted and /or was tossed into the fire.
This chain is divided into four and marked by adjustable lengths marking rod, pole or perches which were different names for 5 1/2 yards. this chain is also marked with tallies which are like those on a metric chain.