From Chapter 1, Section 2:
Directions for measuring with the Chain.
The Chain contains in Length 4 Pole or 66 Feet, divided into 100 Links, each Link being 7 92/100 Inches, as aforesaid, having a large Ring exactly in the middle of the Chain, and pretty large Pieces of Brass of different Shapes at the end of each 10 Links, for the speedier counting of the odd Links; also you may tie a large red Rag at 50 Links, and others of a lighter Colour at 25, from each end of the Chain, especially when the Grass is long.
Take care that they who carry the Chain deviate not from a strait Line, (that being the nearest Distance that can be between any two Places,) for if the Lines be not exactly measured, neither the Form nor Content of the Plott can be true. Provide a Staff just six Foot seven Inches and 2/10 long, which divide into 10 equal Parts, so will the Whole be the Length of 10 Links, and each Part the Length of one Link, and 10 times the Length of this Staff (which you may call the off-set Staff) the Length of the whole Chain; also provide 9 Arrows or small Sticks above a Foot long, which you may mark at the Tops with Bits of red Cloath, and at the Bottom you may put small Iron Ferrills and two strait Staves about 5 Foot each.
Before you measure with the Chain, 'tis necessary to examine its Length by the off-set Staff, stretching it on level Ground in such sort, as when you measure with it.
Being thus provided, let the Leader of the Chain take the nine Arrows in his Hand, and one of the 5 Foot Staves, and let the Follower, standing at the Station, direct him to place his Staff at the Chain's End, in a right Line with the Stations, and there to put down one of his Arrows, and then go on.
Let the Follower, being come to the Arrow, take it up, and put his Staff in the place thereof, and direct the Leader to place his Staff as before; then let the Leader, standing at his Staff, look back towards the last Station, and he will see the two Staves and the Station in one right Line, if they have directed right; but if not, the Leader must direct the Follower to place his Staff in the same right Line with the Station and the Leader's Staff, and so must each direct the other, till the two Staves and two Stations are in one right Line.
Let 'em thus proceed till they have measured to the Station, or till the Leader is nearer the Station than one Chain's Length; then will the Number of whole Chains measured, be express'd by the Number of Arrows prick'd down, suppose 7; and the Leader holding the End of the Chain to the Station, and the Follower will see how many Links are contain'd between the Station and last Arrow, suppose 60.
Now enter in the Field Book, the Chains and Links without any Distinction between them, and they will be 760 implying either 760 Links, or 7 Chains 60 Links; but the Links must always possess two Places after the Chains, as 7 Chains 4 Links must be written 704, and not 74; and 8 Chains must be written 800, also as soon as you have measur'd each Length, enter it down immediately in the Field Book, and never trust to your memory; also at the end of each Length, inquire of the Leader and Follower how many Arrows each have in their Hands, and if the Sum of the Arrows are not nine, the last measur'd Length is doubtful, and must be re-measur'd before you proceed.
When the Length is above nine Chains, let the Leader go on, and set his Staff down at the tenth, and let the Follower put his Staff in the place of the Leader's, and give the Leader the nine Arrows, and then proceed as before; but enter these 10 Chains immediately in the Field Book, and if the Length is 10 Chains more, enter 20; also observe it is usual to allow 5 Links from the Stem of the quickset Hedge, for the Breadth of the Ditch, except the Custom or Agreement is otherwise; but the Custom of the Place generally is the Surveyor's Rule.