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As long as there has been commerce, humankind has used measuring apparatus. This may have been as simple as a stick of wood comparing lengths of cloth, or scales comparing weights of produce, or crude containers comparing volumes of grain — to say nothing of the fact that days have been divided into segments for at least five millennia.

Virtually every aspect of our lives is governed by the measurement of some quantity. From the amount of milk you pour over your cereal, to the length of time you spend at work or school, to the temperature of your home, someone or some automatic device is measuring a quantity that affects you — directly or indirectly — every hour of every day.

The science of measurement is called metrology, and this profile describes a few of the Museum's measuring devices. Measurements may be simple in concept, such as your shoe size, or extremely complex — such as the distance from Earth to an object at the edge of the Universe. In today's world, however, all measurements have one thing in common: they depend on a foundation of standards overseen by a governing authority.

Today, we depend on seven fundamental units: length, mass, time, temperature, electric current, luminous intensity and quantity (the Museum's collection does not currently include standards directly related to temperature, luminous intensity or the mole) the measuement of mass. All measurement units are derived from these, and, with these seven base units, we can measure volume, power, energy, electric resistance, area, pressure and much, much more! (For scientific definitions of each fundamental unit, see http://www.bipm.fr/enus/3_SI/base_units.html

Measuring the mass of a juicy steak accurately to a few grams is fine, but the amount of active ingredient in medication, for example, needs to be measured to a few milligrams in order to avoid serious consequences. No measurement is perfect, however, and there is uncertainty associated with all standards. How precisely and/or accurately the information must be varies from use to use. (See http://physics.nist.gov/cuu/index.html for the difference between accuracy and precision and error and uncertainty.)

The Museum's metrology collection contains more than 400 artifacts, comprising an eclectic selection of measuring devices. (Further details on each may be accessed by clicking on the image.) Most of these predate a change in the 1960s from the use of physical standards to the use of physical phenomena.

The Museum's collection includes linear measuring devices (800617*, 800641 and 800650) used by weavers from the sixteenth- to eighteenth-century; artifacts which served as the primary physical standards in Canada during the eighteenth and nineteenth centuries, and equipment that measures physical phenomena as standards: e.g., the Krypton-86 light source used in measuring length.

Examples of rules used by weavers in eastern Europe between the sixteenth and eighteenth centuries. The lines on the rules and the "combs" were used to define the patterns on rugs and other woven items. (Top to Bottom, 800617, 800641 and 800650) Rules

The collection also includes devices used by field inspectors to verify commercial apparatus, including a gauge (950502) which measures the size of lobsters in relation to fisheries regulations.

Gauge This device (950502) was used to measure shells on the bodies of lobsters, circa 1980. The shell had to exceed the gauge's minimum separation: 2 1/2 inches for "canner" lobsters, or 3-3/16 inches for "market" lobsters. Made by W. & A. Moir, Halifax, N.S.

* These 6-digit numbers refer to the Museum's artifact acquisition numbers.