Ralston stability indicator, in a wooden box. From 'Ocean Monarch' ex 'Empress of England' built 1957 for Canadian Pacific. Later owned by Shaw Savill Line. The background and design basis of this instrument are described by Shirley Brooks Ralston (1874-1952) in his paper in the 1911 INA transactions (Vol 53 part 1) and supported by 6 patents (3 UK in 1910 1920 & 1935, 1 French and 2 US 1914 & 1935). He was the Naval Architect at the Linthouse Yard of Alexander Stephen & Sons Ltd from around 1910 (joining the board as director from 1921) until his death in 1952. It appears that every commercial ship built by the yard from 1910 until the early 1960s was supplied with one of these instruments to assist the first officer with his trim & stability calculations - in effect an early analogue stability computer. They fell out of use only when replaced by electronic Loadicators and latterly shipboard computers [information Ian Winkle]