on 2003-06-20 11.14, Norman & Nancy Werling at [EMAIL PROTECTED] wrote:
> I recall that my father, a farmer, used a > measure of rods, which I think were 16.5 feet and I think that was normally > the distance between fence posts. in response to my observation: > I have no doubt that this block was originally surveyed as 66 feet (1 chain) > by 165 feet (2 1/2 chains) and it was then known locally as a 'quarter acre > block' This is a very common, perhaps the most common, land size in > Australian cities. Your memory of your father's rod fits well with land sizes here. A restatement of the measurements of our house block would be: 'I now believe that this block was originally surveyed as 4 rods (1 chain) by 10 rods (2 1/2 chains) and it was then known locally as a 'quarter acre block' This is a very common, perhaps the most common, land size in Australian cities'. This also fits in well with Edmund Gunter's original concept of the measuring chain. Edmund Gunter (1581/1626) divided his measuring chain into 100 links and also into 4 rods (poles or perches). In this way surveyors could carry out their calculations using the easier decimal calculations, but could then report their results using the older binary (halves, quarters, and eighths) to their clients. [It is interesting that Simon Stevin's 'De Thiende' (Of Tenths) was published in 1585 � when Edmund Gunter was four years old.] Suppose that Gunter needed to add two lengths, say 1.23 chains and 4.56 chains. He would add these to get 5.79, and then report this as follows 5 chains 3 rods (and 4 links). The 4 links (each of 7.92 inches exactly) could then be calculated to be 31.68 inches or about 2 feet 7 87/128ths inches, so the final report would read: 5 chains 3 rods 2 feet 7 87/128ths inches (approx). Gunter's dual purpose measuring chain thus had two advantages. It made calculations easy for surveyors, and, by reporting in old binary units, it made the surveyors appear to their clients to be special talented persons, as the clients could not carry out the calculations with the same ease as the surveyors! Andro Linklater, in his book 'Measuring America' (Walker 2003), gives a better description of the dual nature of Gunter's Chain as both a decimal and a binary measuring instrument. Linklater also explores some of the possibilities of these dual land measuring methods for more complex problems such as area calculations. Cheers, Pat Naughtin LCAMS Geelong, Australia Pat Naughtin is the editor of the free online newsletter, 'Metrication matters'. You can subscribe by sending an email containing the words subscribe Metrication matters to [EMAIL PROTECTED] --
