2-8-4 was a passenger derivative of the Class FD 1’E1’-h2 (2-10-2) freight locomotive and had many parts in common with the Class FD. The Soviet 2-8-4 was the most numerous single Berkshire class built in the world. Kolomna Locomotive Works built the first four locomotives. In 1935, production was transferred to the enlarged and modernised former which was renamed Voroshilovgrad Locomotive Works. A lotal of 649 locomotives of the two variants, Class IS20 and Class IS21 (later Class FDp), were built between 1932 and 1942. After Germany attacked the Soviet Union on 22 June 1941, the Russians evacuated all semi-completed class
Minim (unit) size of a drop can vary considerably depending upon the viscosity and specific gravity of the liquid. (At the time, the phenomenon of surface tension was not well understood.) The minim, on the other hand, was measured with a graduated glass tube known as a "minimometer", later known as the minim-tube. The minim-tube was a type of graduated pipette, a device invented in 1791 by François-Antoine-Henri Descroizilles. Apothecaries' measures are fully defined in the United Kingdom's Weights and Measures Act of 1878, but the UK's 1963 Weights and Measures Act provided for the abolition of the minim, fluid scruple, and