Henry Edward Armstrong
Henry Edward Armstrong (1848-1937) was an English chemist. He was born (and lived all his life) in Lewisham, a suburb of London. In the spring of 1865 he entered the Royal College of Chemistry in London (now the department of chemistry at Imperial College). Chemical training in those days was not lengthy, and at the age of 18 he was selected by Edward Frankland to assist him to devise methods of determining organic impurities in sewage. His Ph.D. was awarded in 1869 for his work on on "acids of sulfur." A permanent appointment in 1879 at City and Guilds of London Institute (now also a part of Imperial College) followed. At age 36, Armstrong became Professor of Chemistry at another Imperial College precursor, the Central Institution in 1884. He already had started on the systematic synthesis, degradation and structural constitution of many naphthalene derivatives in 1881, building on earlier work on benzene derivatives and Erlenmeyer’s proposal for the structure of naphthalene. W. P. Wynne was his most important collaborator; their collection of 263 naphthalene samples accrued over several decades is now preserved at Imperial College as the Armstrong-Wynne Collection. This work gave much impetus to the synthetic dye industry. His later researches dealt with terpenes, particularly camphor, with water purification, helping to eradicate typhoid fever and with crystallography.
In 1887, Armstrong became interested in classifying substituents of benzene in terms of their meta- and ortho-para directing influences. It was in a footnote to an article on that theme in 1890 that his centric formula for benzene first appeared. His six affinities acting within a cycle anticipate both the electron, modern theories of aromaticity and arguably since he recognised that affinities have direction and are not merely point particles, even the wave mechanical theories of the 1920s.[citation needed]