How We Got Here: The Origins of metrology

In recent years, Hexagon Manufacturing Intelligence has been on a journey, expanding on our expertise in metrology to include technologies that collect data across the manufacturing process to improve quality and drive productivity.

When we look at the history of measuring, mankind has been on a journey too, and it’s amazing to see just how far metrology has come in terms of accuracy, reliability, and quality.

Egyptian-cubit Origins of metrology blogThe Human Body
The earliest attested standard measure was based on the length of the human forearm. In ancient civilisations, the ‘cubit’ measured the length from the elbow to the tip of the middle finger. Using cubit rods, the ancient Egyptians ‘standardised’ this length with the ‘royal cubit’, represented in Egyptian Hieroglyphics by a forearm symbol. Several rods have survived in tombs, though comparisons have shown they range in length from 523 mm to 529 mm.

The palm provided numerous different units based on various lengths of the human hand. In ancient Mongolia, an ‘ald’ was the length of a man’s outstretched arms. An ‘onyx’ referred to the length of a human fingernail.

Many standardised units used today have anthropic origins. An inch was the breadth of the last thumb-joint. A yard was the distance from the tip of the nose to the outstretched fingers of the right arm. I don’t need to tell you which body part inspired the foot!

Taking the human body as a standard created a huge degree of inconsistency and variation. Typical attempts to overcome this involved defining the lengths against one individual, usually the king or another important figure. Even today, we haven’t necessarily mastered the science of standardisation! Farming 
Oxen not only helped our ancestors produce crops; they also helped yield some interesting metrological methods. If you wanted to measure the area of land your one oxen could plough in a day you would call that an oxgang. An acre was the amount of land ploughed by a pair of oxen. If you were lucky enough to have eight oxen, the amount of land they could plough in a season was called a carucate.

More successful attempts at standardisation may have begun over 4 500 years ago. A broken ruler unearthed from Mohenjo-daro in Pakistan is marked at exact intervals of 0.264 inches. Subdivisions on the ruler are said to have a maximum error of 0.005 inches! Weights found there also appear to be cut to central standards.

Over time, measuring standards became more regulated. In the United States, the Constitution (1789) gave congress the power to ‘fix the standard of weights and measures’. In 1901, this power was transferred to the National Institute of Standards and Technology (NIST). The Metric Act of 1866 legally recognised the metric system in the US, and the original bill included a now-obsolete definition of the metric system and tables of units!

In the UK, the National Physical Laboratory (NPL) was established in 1900. In a basement at the NPL is a copy of the international prototype kilogram (IPK), which is made of ten per cent iridium and 90 per cent platinum. The problem with defining the kilogram’s mass against a physical object like the IPK is that it could be affected by environmental changes or maybe even damaged. A key focus for the NPL is to find a way of defining the kilogram more accurately against a fundamental constant (an example of which is the metre, which is defined as the length of the path travelled by light in vacuum during 1/299 792 458 of a second).

So it goes to show that, even today, we haven’t necessarily mastered the science of standardisation!

Looking to the Future
At some point in history, an ancient Egyptian looked at the cubit and realised, ‘This isn’t accurate. This needs to change.’ The attempt at standardisation might have been primitive, but it was an act of progress. It was our ancestors building on these numerous acts of progress throughout history that brought us to where we are today.

Progress is change. It’s about seeing things as they are and having the foresight to see things as they should be. At Hexagon Manufacturing Intelligence, we enable organisations to close that gap by developing the big ideas of today into the technologies of tomorrow.

The change shaping manufacturing today is the need for greater connectivity, creating a seamless production cycle that drives productivity.

Click here to find out how our origins in metrology are helping us shape smart change in manufacturing.


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