Julius Neßler was a German

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 chemist

Chemist

A chemist is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties such as density and acidity. Chemists carefully describe the properties they study in terms of quantities, with detail on the level of molecules and their component atoms...

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He discovered the Nessler's reagent

Nessler's reagent

Potassium tetraiodomercurate is an inorganic compound containing potassium cations and the tetraiodomercurate complex anion. It is mainly used as Neßler's reagent, a 0.09 mol/L solution of potassium tetraiodomercurate in 2.5 mol/L potassium hydroxide, used to detect ammonia.-Nessler's...

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Biography

Neßler studied at the University of Freiburg

University of Freiburg

The University of Freiburg , sometimes referred to in English as the Albert Ludwig University of Freiburg, is a public research university located in Freiburg im Breisgau, Baden-Württemberg, Germany.The university was founded in 1457 by the Habsburg dynasty as the...

 from 1853 to 1856, when he attained his PhD. After his Ph.D. Neßler worked for some months with Lambert Heinrich von Babo

Lambert Heinrich von Babo

Lambert Heinrich von Babo was a German chemist.-Life:Babo was the son of the agronomist Lambert Joseph von Babo and his first wife Karoline Ehrmann. The oenologist August Wilhelm von Babo was his half-brother...

 and Robert Wilhelm Bunsen and then joined a chemical company in Karlsruhe.

Nessler cylinder

A Nessler cylinder

Nessler cylinder

Nessler cylinders are laboratory tubes with a fixed volume. On the walls there are marks of the nominal stroke volume and possibly one half-way mark...

  is a simple type of colorimeter

Colorimeter

For articles on Colorimeter see:* Colorimeter * Tristimulus colorimeter...

. It is best-known for use with Nessler's reagent but can be used for any colorimetric chemical test

Chemical test

In chemistry, a chemical test is a qualitative or quantitative procedure designed to prove the existence of, or to quantify, a chemical compound or chemical group with the aid of a specific reagent...

. In practice, a pair of tubes is used, set on a white background. One tube is filled with color reagent and a known quantity of sample to act as a reference. The sample to be tested is mixed with color reagent in a beaker

Beaker (glassware)

A beaker is a simple container for stirring, mixing and heating liquids commonly used in many laboratories. Beakers are generally cylindrical in shape, with a flat bottom. Most also have a small spout to aid pouring as shown in the picture...

 and the color is allowed to develop. The mixture is then poured, a little at a time, into the second tube until the depth of color in the two tubes is identical. The heights of the liquid columns in the two tubes are measured and the concentration of the sample solution can be calculated using the Beer–Lambert law.