The state of education in arithmetic is highlighted by the publication of the first clear explanation of the significance and use of decimal fractions by the Dutch civil engineer Simon Stevin in 1585. That is, at about the time of the first explorations of Virginia, computation with decimal fractions was still a mystery.
Aaron Rathbone, an English surveyor invented a decimal chain for surveying, based on the 16½ foot length of the Statute Pole . This was first described in 1616 and was adopted by many English surveyors because it made calculations simpler. Rathbone’s chain was superseded by the improved chain introduced by Edmund Gunter in 1620. Gunter’s chain became the standard distance measuring instrument in the English-speaking world and endured for well over two hundred years.
Gunter’s chain was 66 feet long, i.e., it was four poles long. It had one hundred links with each tenth link marked by a brass ring. The result was the following table of equivalents:
In area measurements, a square of 10 chains on each side would be equal to 435,600 square feet or 10 acres.
(It is interesting to note that the furlong is used in horse racing to describe fractional miles.)
Another improvement in the field in the late Sixteen Century was the use of the tripod as opposed to a single rod. Another innovation was the plane table, a flat surface that was taken to the field for holding a piece of paper. As a survey was being made, the plot of the tract could be made on paper on the plane table. In 1616, appeared the first printed work describing how to make and use a field book for keeping a record of the work done.
Computational scales, especially useful in working with a scale drawing, appeared in the late Seventeenth Century.
Gunter, a revered name among surveyors, was born in 1581 and became an Oxford-trained mathematician and astronomer. His practical applications were to simplify the calculations made for seafaring navigators. A by-product of this work was applicable to surveying.
It is seen that major improvements in surveying started the last half of the 1500s and extending up to about 1700. There were revolutionary changes in the period.
(03 Mar 05)
We gratefully acknowledge the work of John Blankenbaker who published over 2,500 Germanna History Notes via the Germanna-L@rootsweb.com email list from 1997 to 2008. We are equally thankful to George Durman (Sgt. George) for hosting the list and republishing the notes via rootsweb.com.