OK Willie, since you did that, i'll add this to help with units of measure

Oh those Brits... great sense of humor!

Gunter's Chain:

"Dimensurator or Measuring Instrument whereof the mosts usual has been the **Chain**, and the common length for English Measures 4 **Poles**, as answering indifferently to the Englishs **Mile** and **Acre**, 10 such Chains in length making a **Furlong,** and 10 single square Chains an Acre, so that a **square Mile ** contains 640 square Acres." ---John Ogilby, Britannia, 1675

Gunter divided the chain into 100 ** links**, marked off into **groups of 10 by brass rings** which simplified intermediate measurement. On the face of it, the dimensions make no sense: Each link is a fraction under 8 **inches ** long; 10 links make slightly less than 6 **feet**, 8 inches and a full length of 66 feet.

The **chain** as a unit of length of 66 feet and the **link,** one-hundredth of a chain, probably developed as a result of the introduction of Gunter's chain as the technique of surveying; but it is important not to confuse the two; Gunter's chain is the physical device used in the field. A chain also had the commonly used subunit variously called a "**rod," ** a "**pole**" or a "**perch," ** which was 16.5 feet long, or one fourth of a chain.