The Baumé scale is a pair of

hydrometer A hydrometer or lactometer is an instrument used for measuring density or relative density of liquids based on the concept of buoyancy. They are typically Calibration, calibrated and Graduation (instrument), graduated with one or more scales suc ...

scales developed by French pharmacist

Antoine Baumé Antoine Baumé (26 February 172815 October 1804) was a French people, French chemist. Life He was born at Senlis, Oise, Senlis. He was apprenticed to the chemist Claude Joseph Geoffroy, and in 1752 was admitted a member of the École de Pharmaci ...

in 1768 to measure

density Density (volumetric mass density or specific mass) is the ratio of a substance's mass to its volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' (or ''d'') can also be u ...

of various liquids. The unit of the Baumé scale has been notated variously as ''degrees Baumé'', ''B°'', ''Bé°'' and simply Baumé (the accent is not always present). One scale measures the density of liquids heavier than water and the other, liquids lighter than water. The Baumé of distilled water is 0. The

API gravity The American Petroleum Institute gravity, or API gravity, is a measure of how heavy or light a petroleum liquid is compared to water: if its API gravity is greater than 10, it is lighter and floats on water; if less than 10, it is heavier and sinks ...

scale is based on errors in early implementations of the Baumé scale.

Definitions

Baumé degrees (heavy) originally represented the percent by mass of sodium chloride in water at . Baumé degrees (light) was calibrated with 0°Bé (light) being the density of 10% NaCl in water by mass and 10°Bé (light) set to the density of water. Consider, at near room temperature: * +100°Bé (specific gravity, 3.325) would be among the ''densest'' fluids known (except some liquid metals), such as

diiodomethane Diiodomethane or methylene iodide, commonly abbreviated "MI", is an organoiodine compound. Diiodomethane is a very dense colorless liquid; however, it decomposes upon exposure to light liberating iodine, which colours samples brownish. It is slig ...

. * Near 0°Bé would be approximately the density of water. * −100°Bé (specific gravity, 0.615) would be among the ''lightest'' fluids known, such as liquid

butane Butane () is an alkane with the formula C4H10. Butane exists as two isomers, ''n''-butane with connectivity and iso-butane with the formula . Both isomers are highly flammable, colorless, easily liquefied gases that quickly vaporize at ro ...

. Thus, the system could be understood as representing a practical spectrum of the density of liquids between −100 and 100, with values near 0 being the approximate density of water.

Conversions

The relationship between specific gravity (s.g.; i.e., water-specific gravity, the density relative to water) and degrees Baumé is a function of the temperature. Different versions of the scale may use different reference temperatures. Different conversions formulae can therefore be found in various handbooks. As an example, a 2008 handbook states the conversions between specific gravity and degrees Baumé at a temperature of : :

\displaystyle\frac &\text \end \end

The numerator in the specific gravity calculation is commonly known as the "modulus". An older handbookSmithells, Colin J. and Al. 'Metals Reference Book', London Butterworths Scientific Publications, 1949. Page 41 gives the following formulae (no reference temperature being mentioned): :

\displaystyle\frac &\text \end

Other scales

Because of vague instructions or errors in translation a large margin of error was introduced when the scale was adopted. The

scale is a result of adapting to the subsequent errors from the Baumé scale. The Baumé scale is related to the Balling,

Brix Degrees Brix (symbol °Bx) is a measure of the dissolved solids in a liquid, based on its specific gravity, and is commonly used to measure dissolved sugar content of a solution. One degree Brix is 1 gram of sucrose solute dissolved in 100 grams ...

Plato Plato ( ; Greek language, Greek: , ; born BC, died 348/347 BC) was an ancient Greek philosopher of the Classical Greece, Classical period who is considered a foundational thinker in Western philosophy and an innovator of the writte ...

and '

specific gravity Relative density, also called specific gravity, is a dimensionless quantity defined as the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for solids and liquids is nea ...

times 1000' scales.

Use

Before standardization on

around the time of

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

the Baumé scale was generally used in industrial chemistry and

pharmacology Pharmacology is the science of drugs and medications, including a substance's origin, composition, pharmacokinetics, pharmacodynamics, therapeutic use, and toxicology. More specifically, it is the study of the interactions that occur betwee ...

for the measurement of density of liquids. Today the Baumé scale is still used in various industries such as sugar beet processing, ophthalmics,

starch Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diet ...

industry, winemaking, industrial water treatment, metal finishing, and printed circuit board (PCB) fabrication. It is also used for caustic in refining process.

Definitions

Conversions

Other scales

Use

See also

Notes

References

Further reading