Why old units looked the way they did
Before international standards, people measured with what they had: body parts, grain, daily work and containers. A cubit was the length of a forearm, a foot was a foot, and an acre was the area a team of oxen could plough in a day. These units were practical but varied from town to town, which made trade difficult.
The metric system, introduced in France in the 1790s, replaced thousands of local units with a single decimal system. Today the International System of Units (SI) defines every unit from fixed constants of nature, yet many old units survive in everyday speech, horse racing, jewellery, shipping and cooking.
Values in the museum are the commonly accepted modern equivalents. Many historic units changed over time and place, so treat them as typical values.