Convert Millimeters to Chains (mm to ch) ▶
How to convert
1 chain (ch) = 20116.8 millimeter (mm). Chain (ch) is a unit of Length used in Standard system. Millimeter (mm) is a unit of Length used in Metric system.
Chain: A Unit of Length Used for Measuring Land
The chain is a unit of length that is equal to 66 feet or 22 yards or 4 rods or 100 links. It is part of the US customary and imperial measurement systems. It is used for measuring land, especially in surveying and mapping. The symbol for chain is ch. There are 10 chains in a furlong, and 80 chains in one statute mile. An acre is the area of 10 square chains. The unit is named after the chain, a measuring device that was invented by Edmund Gunter, a clergyman and mathematician, in the 17th century. The chain is also sometimes called a Gunter’s chain, a surveyor’s chain or a land chain. In this article, we will explore the definition, history, usage and conversion of the chain as a unit of length.
Definition of the Unit
The chain is a unit of length that is equal to 66 feet or 22 yards or 4 rods or 100 links. It is one of the base units in the US customary and imperial measurement systems, along with the foot, the yard and the mile. The chain is also a derived unit in the International System of Units (SI), which is the most widely used system of measurement in the world. The SI base unit of length is the meter, which is defined as the length of the path travelled by light in vacuum during a time interval of 1/299792458 seconds.
The definition of the chain has not changed since its introduction by Edmund Gunter in 1620, who based it on an earlier English unit called an acre’s breadth, which was equal to one-tenth of a furlong or one-eightieth of a mile. However, the definition of the foot, which is used to define the chain, has changed several times over time, as different standards and methods of measurement were adopted by various countries and regions. The current definition of the foot as 0.3048 meter was agreed upon by an international treaty in 1959.
History of the Unit
The origin of the chain as a unit of length can be traced back to 1620, when Edmund Gunter created a measuring device called a chain. The chain was 66 feet long and consisted of 100 metal links connected by three rings each. The links were made of thick wire with a loop at each end. The chain had brass handles at each end for holding and folding. Gunter chose this unit because it was convenient for his work on surveying and mapping land. He also named this unit after himself, as he wrote in his book: "I have taken as unit for these measurements one hundredth part [of a furlong], which I will call an Chain".
Gunter’s unit was soon adopted by other surveyors and mapmakers, who found it useful for measuring distances and areas on flat or gently sloping land. The chain was also used for laying out roads, railways and canals. The chain became part of the US customary and imperial measurement systems, which were based on earlier English units that were brought by British settlers to America. The chain was also used in some other countries influenced by British practice, such as Canada and India.
In 1785, when the United States Congress passed the Land Ordinance Act to survey and divide the public land west of the Appalachian Mountains into rectangular townships and sections, the use of the chain as a unit of measurement was mandated by law. The act also defined the chain as equal to four rods or poles or perches. The surveyors who carried out this work were known as "chain bearers" or "chain carriers", and they marked each mile along their survey lines with wooden posts called "milestones".
In 1959, when the United States, Canada, the United Kingdom and some other Commonwealth countries agreed to adopt a common definition of the foot as 0.3048 meter, based on the international yard that was defined as 0.9144 meter by an international treaty in 1959, the chain became exactly equal to 20.1168 meters.
Usage of the Unit
The chain is a unit of length that is used for measuring land, especially in surveying and mapping. The chain is also used for measuring distances on roads, railways and canals. The chain is still used in some rural areas and historical contexts in the United States, Canada and some other countries that follow the US customary or imperial measurement systems.
The chain is used for various purposes, such as:
How to Convert
The chain can be converted to other units of length by using conversion factors or formulas. Here are some examples of how to convert chains to other units of length in the US customary system, the imperial system and the SI system:
Equivalents in Other Units and Scales
The chain can be expressed in terms of other units of length by using equivalent values or ratios. Here are some examples of how to express chains in other units of length:
Millimeter: A Unit of Length
Definition of the millimeter
A millimeter is a unit of length in the metric system, which is based on the International System of Units (SI). It is defined as one thousandth of a meter, which is the SI base unit of length. One millimeter can be written as 1 mm or 0.001 m.
How to convert millimeter to other units of length
To convert millimeter to other units of length, we need to use conversion factors that relate the millimeter to the desired unit. For example, to convert millimeter to centimeter, we need to know that 1 cm = 10 mm, so we can divide the number of millimeters by 10 to get the number of centimeters. Similarly, to convert millimeter to inch, we need to know that 1 in = 25.4 mm, so we can divide the number of millimeters by 25.4 to get the number of inches.
Here are some common conversion factors for millimeter and other units of length in the US standard system and the SI system:
Where millimeter is used
The millimeter is a widely used unit of length in many fields and applications around the world. Some examples are:
History of millimeter
The millimeter has a long and varied history in different countries and cultures. Some historical facts are:
Example conversions of millimeter to other units
Here are some examples of how to convert millimeter to other units of length using the conversion factors given above:
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