Moritz Immisch (12 March 1838 – 20 September 1903) was an Electrical engineer, watchmaker and inventor. He was born on 12 March 1838 in Niederschmon, near Querfurt in Germany and died 20 September 1903 in London. Always known as 'Moritz Immisch', his full name was Karl Moritz, the eldest son of August Christian Immisch, a watchmaker. He received a technical education in the state of Thuringia, graduating from university in his native country, before leaving Germany around 1860 to seek opportunities in England, particularly in London. He migrated with one of his younger brothers, Bernhardt Theodore Immisch, who had also trained as a watchmaker with their father. Both settled in England; Moritz marrying Emma Elizabeth Welch at St John's Church, Marylebone, London in 1876. Twenty years later, at the request of his English family Moritz became a naturalised British citizen. Watchmaking Immisch found opportunities to apply his watchmaking skills, developing precision clockwork mechanisms, improving practical details and considering the further applications of the physical processes involved. From 1863 he was employed as foreman to the noted firm Le Roy & Fils at their premises on Regent St. In 1872, when already a Council Member of the British Horological Institute, he submitted an essay on 'The balance spring and its isochronal adjustments' which was awarded the Institute's Baroness Burdett Coutts Prize Immisch's prize essay was published in book form - a work which remained in print for many years. Instrument making In 1881 Immisch obtained a patent for a remarkably small watch-shaped thermometer, functioning on the variable expansive properties of fluid in a Bourdon tube. This metallic instrument was designed to be more robust than contemporary glass thermometers filled with mercury - for this reason it was first branded as an 'avitreous', or metallic thermometer. The speed of the temperature-expansion and the calibration of the watch-dial indicator allowed very accurate readings to be taken, and its small size made it highly portable as a clinical instrument. Hundreds of Immisch thermometers were tested for accuracy at the Kew Observatory every year after its launch. It was awarded a Silver Medal at the International Medical Congress of 1881 and received awards at the Inventions Exhibition of 1885 in London, as well as the Exposition Universelle in Antwerp and the Gewerbe und Industrie Ausstellung in Görlitz, also in 1885. Its small size made the device very popular and it was referred to in many