Hermann Sprengel FRS (29 August 1834 – 14 January 1906) was a German-British

chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties. Chemists carefully describe th ...

who discovered the explosive nature of

picric acid Picric acid is an organic compound with the formula (O2N)3C6H2OH. Its IUPAC name is 2,4,6-trinitrophenol (TNP). The name "picric" comes from el, πικρός (''pikros''), meaning "bitter", due to its bitter taste. It is one of the most acidic ...

in 1873, patented safety explosives and invented the mercurial air pump.

Life

He was born at Schillerslage, near

Hanover Hanover (; german: Hannover ; nds, Hannober) is the capital and largest city of the German state of Lower Saxony. Its 535,932 (2021) inhabitants make it the 13th-largest city in Germany as well as the fourth-largest city in Northern Germany ...

, on 29 August 1834. Sprengel was the son of George Sprengel. He was educated in

Göttingen Göttingen (, , ; nds, Chöttingen) is a college town, university city in Lower Saxony, central Germany, the Capital (political), capital of Göttingen (district), the eponymous district. The River Leine runs through it. At the end of 2019, t ...

and earned his degree at the university at

Heidelberg Heidelberg (; Palatine German language, Palatine German: ''Heidlberg'') is a city in the States of Germany, German state of Baden-Württemberg, situated on the river Neckar in south-west Germany. As of the 2016 census, its population was 159,914 ...

in 1858. He moved to England the following year and became a naturalised British subject. He was first employed as an assistant in chemical laboratory in Oxford and then moved to London to work at Guy's and St Bartholomew's Hospitals, before working in the chemical works of Thomas Farmer of Kennington (1865-1870). There he invented a generic class of materials called

Sprengel explosive Sprengel explosives are a generic class of materials invented by Hermann Sprengel in the 1870s. They consist of stoichiometric mixtures of strong oxidisers and reactive fuels, mixed just prior to use in order to enhance safety. Either the oxidiser ...

s. In addition he invented a very robust and continuously operable device called the

Sprengel Pump The Sprengel pump is a vacuum pump that uses drops of mercury falling through a small-bore capillary tube to trap air from the system to be evacuated. It was invented by Hanover-born chemist Hermann Sprengel in 1865 while he was working in Londo ...

which could reduce the amount of air in a chamber to one-millionth of its volume paving the way for the filament light bulb. He was elected a

Fellow of the Royal Society Fellowship of the Royal Society (FRS, ForMemRS and HonFRS) is an award granted by the judges of the Royal Society of London to individuals who have made a "substantial contribution to the improvement of natural science, natural knowledge, incl ...

in 1878. His candidature citation read "''Distinguished as a Chemist and Physicist. Author of the following researches. *(1) Ueber einen neuen Lothrohrapparat (Pogg Ann v 112 1861) *(2) On the detection of Nitric Acid (J Ch Soc 1865) *(3) Researches on the vacuum (J Ch Soc 1865) *(4) On determining the weight of heterogeneous liquids (J Ch Soc 1866) *(5) Improvements in the preparation of Explosive compounds *(6) The water air-pump (Phil Mag, 1873) *(7) An Air-bath of constant temperature between 100 degrees & 200 degrees C (J Ch Soc 1873) *(8) A method of determining the Specific Gravity of liquids with ease & great exactness (J Ch Soc 1873 & Pogg Ann 1874) *(9) A new class of explosives which are non-explosive during their manufacture storage & transport (J Ch Soc 1873) *(10) Use of water "atomiser" in production of Sulphuric Acid (Ch News 1875).'' " He died at 54 Denbigh Street, London, S.W., on 14 January 1906, and was buried in

Brompton Cemetery Brompton Cemetery (originally the West of London and Westminster Cemetery) is a London cemetery, managed by The Royal Parks, in West Brompton in the Royal Borough of Kensington and Chelsea. It is one of the Magnificent Seven cemeteries. Estab ...

. He had never married.

Life

References

Further reading