Hello!

In all traditional measuring systems, humans used their bodies as measuring standards, which is why some units are still based on the dimensions of the human body.

The inch represents the width of a thumb, which is why, in many languages, the same word is used for both ‘inch’ and ‘thumb’. In Dutch, duim means both inch and thumb, in French pouce means inch and thumb and in Spanish, pulgar is thumb and pulgada is inch.

The foot was originally the length of a human foot, but it wasn’t 12 inches. It was about 9.8 inches. When the Normans arrived in England, they brought the Roman tradition of a 12-inch foot. Henry I’s government made the 12-inch foot official, and the royal government took steps to make this foot length known. A 12-inch foot was inscribed on the base of a column of St Paul’s Church in London, and measurements in this unit were said to be ‘by the foot of St Paul’s’.

The yard (3 feet) comes from the Old English gerd meaning ‘twig’ and was the distance from the tip of the nose to the end of the middle finger of the outstretched hand. If you stretch your arms out to the sides as far as possible, your total arm span, from one finger tip to the other, is a fathom (6 feet).

Happy Puzzling!