History of Measurement Timeline

Although the Indians had long used decimal numbers for mathematical computation, it was Simon Stevin who in 1585 first advocated the use of decimal numbers for everyday purposes in his booklet De Thiende ('the tenth'). His work argued that decimal fractions could simplify commerce, surveying, and measurement for ordinary people.

Image source: Simon Stevin

Beyond mathematics, De Thiende proposed that decimal divisions be applied to units of money and measurement. This vision directly influenced later reformers who designed decimal currencies and, ultimately, fully decimalized systems of weights and measures.

Image source: De Thiende

Stevin's clumsy notation for decimal fractions was overcome with the introduction of the decimal point, generally attributed to Bartholomaeus Pitiscus, who used this notation in his trigonometrical tables published in 1595. This small typographic innovation made decimal arithmetic dramatically easier and paved the way for decimal metrology.

Image source: Bartholomaeus Pitiscus

In his report, Jefferson proposed calling his base unit of length a 'foot', suggesting it should be either 3/10 or 1/3 of the length of a pendulum having a period of one second — echoing the 'standard' proposed by John Wilkins over a century previously. Congress declined to adopt the scheme.

Image source: Thomas Jefferson

In 1790, Thomas Jefferson submitted a report to the United States Congress in which he proposed the adoption of a decimal system of coinage and of weights and measures. The plan reflected Enlightenment ideals of rationality and uniformity, though only the decimal currency portion was ultimately enacted.

While Jefferson's full proposal for decimal weights and measures stalled, the United States did adopt a decimal system of coinage, with the dollar divided into 100 cents. This made American money one of the earliest decimal currencies, demonstrating the practicality of decimal division.

Image source: United States dollar

Wilkins suggested calling his base unit of length derived from the seconds pendulum a 'foot'. The idea of anchoring measurement to a reproducible physical constant, rather than an arbitrary royal decree or body part, was revolutionary and influenced both Jefferson and the French metric designers.

Image source: Seconds pendulum

In his 1668 essay, John Wilkins proposed a universal measure — a decimal system based on natural phenomena rather than human anatomy. He suggested deriving the base unit of length from the length of a pendulum with a period of one second, anticipating key principles of the later metric system.

Image source: John Wilkins

In 1670, Gabriel Mouton, a French vicar and scientist, published a proposal essentially similar to John Wilkins' universal measure. His base unit of length would have been 1/1000 of a minute of arc (about 1.852 m) of geographical latitude, tying length to the dimensions of the Earth itself.

Mouton's insight that a unit of length should be derived from the Earth's dimensions foreshadowed the definition of the metre as a fraction of the meridian. Though not adopted in his lifetime, his work is recognized as an important precursor to the metric system.

The upheaval of the French Revolution provided the political opportunity for sweeping reform of weights and measures. Revolutionaries viewed the chaotic patchwork of feudal measures as a symbol of oppression and demanded a system that was uniform, rational, and 'for all people, for all time'.

Image source: French Revolution

The French National Assembly charged the Academy of Sciences with devising a new measurement system. Leading scientists, including Lagrange and Laplace, recommended a decimal structure and a length unit derived from the Earth's meridian, combining the ideas of Wilkins and Mouton into a coherent design.

Astronomers Jean-Baptiste Delambre and Pierre Méchain surveyed the meridian arc between Dunkirk and Barcelona to determine the length of the metre as one ten-millionth of the quarter meridian. Despite wars and revolution, their painstaking triangulation produced the data needed to materialize the new standard.

Image source: Arc measurement of Delambre and Méchain

France formally legislated the decimal metric system in 1795, replacing the bewildering variety of traditional units with a single decimal framework. Prefixes indicated multiples and submultiples of ten, making conversion between units radically simpler than in any prior system.

The metric system, first described in 1668 in Wilkins' visionary proposal, was officially adopted by France in 1799 when the metre and kilogram standards were deposited in the national archives. This marked the birth of the first truly international-ready system of measurement.

Within the metric system, the tonne (or metric ton), equal to 1000 kilograms or one megagram, provided a convenient large-mass unit comparable to the customary ton. It replaced the long ton of 2240 pounds and the short ton of 2000 pounds in most international trade.

Image source: Tonne

Over the course of the 19th century, country after country legislated the metric system, drawn by its simplicity and its advantages for science, engineering, and trade. What began as a French revolutionary project gradually became the default language of measurement across continental Europe and beyond.

Image source: Metric system

Building on France's example, international treaties in the late 19th century established permanent bodies to maintain and disseminate metric standards. Signatory nations received copies of the international prototype metre and kilogram, cementing the metric system's role in global science and commerce.

Image source: Metre Convention

Over the 20th century the metric system became the dominant system worldwide, adopted by nearly every nation and used universally in science. However, several countries, including the United States, China, and the United Kingdom, continue to use their customary units, such as the mile, alongside metric measures.