4-8-8-4 the Western Pacific Railroad, which already rostered large 2-8-8-2s and 4-6-6-4s, but diesel locomotives were gaining popularity and soon were able to displace these Big Boy locomotives. 4-8-8-4 A 4-8-8-4 in the Whyte notation for the classification of steam locomotives by wheel arrangement, is a locomotive with a four-wheel leading truck, two sets of eight driving wheels, and a four-wheel trailing truck. These are commonly known as "Union Pacific Big Boys". Other equivalent classifications are: The equivalent UIC classification is refined to '(2′D)D2′' for Mallet locomotives. 4-8-8-4 Big Boys were only produced for the Union Pacific Railroad. Twenty-five such engines
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