The Comptometer was an American mechanical abacus, made by Felt and Tarrant and first launched in the USA in 1887. It was introduced into the UK by Herbert E Robbins Ltd in the early 1900s and soon became a widely used tool in businesses and government departments. The machine replaced armies of male clerks with a smaller group of women ‘computers’. The marriage bar meant that these were invariably young, single women, earning lower pay than their male counterparts and with no career prospects. Senior clerks, supervisors and managers were still men.
Dora’s achievement in winning the large order for HMG in 1921 was used in an advertisement for Robbins’ company, though she is not personally credited. The Comptometer remained in use until the 1960s as it was quicker and easier to use for calculations than the early electronic computers.