The Rotary Club of Emerald and District Welcomed John Parker Surveyor General of Australia 1989-1997 as our guest speaker and we were all fascinated to hear how the measure of the Metre came about. Below are brief notes from his presentation:
- John was Surveyor General – certifying measurements of length – standard measuring tape or instrument for surveyors to check their tapes against
- Surveyors have to prove lengths can be traced back to Australian measurement of length to the metre held in Paris in the late 1790’s
- The determination of the Metre during the French Revolution
- 1700’s 800 names the Ancient Regime of France employed for a weights and measures = 250k units of weights and measures
- The scientists wanted to do something about it and to be adopted internationally
- French Revolution against government, monarchy etc – wanted something new and different therefore an opportunity to have one unit of weight, length and volume
- International Standard to be set
- June 1792 two astronomers Jean Delambres headed north and Pierre Merchain headed south each had measuring equipment
- Their mission was to measure the world – measured the line of longitude from Dunkerque through Paris to Barelona – mtr was to be 1/10millionth of distance from North Pole to the Equator
- They travelled for 7 years partly because of the French Revolution, local trust in the process (locked up by some councils), Merchain headed south and France was at war with Spain.
- Used Triangulation to measure the distance
- Observed the latitude of Dunkerque and Barcelona – could check distance of 90 degrees
- Results of labours enshrined in a bar of platinum (very stable metre) – still kept in Paris locked away
- Made replicas of the metre bar and distributed to each nation wanting to be part of the standardisation
- Australia holds one of the copies in Sydney
- Surveyor General’s standard tape is checked against this
- Surveyors check their measures against this too – surveyors always take temperatures as steel varies with temperature
- Electronic equipment still has to be tested against the standard
- Also of interest to members would be the survey of India by Everest!
To find out more John recommends the book The Measure of All Things by Ken Alder or visit this great YouTube video