Robert Angus Smith (15 February 1817–12 May 1884) was a Scottish chemist, who investigated numerous environmental issues. He is famous for his research on air pollution in 1852, in the course of which he discovered what came to be known as acid rain. He is sometimes referred to as the 'Father of Acid Rain'.Born Pollokshaws, Glasgow, Smith was educated at the University of Glasgow in preparation for ministry in the Church of Scotland but left before graduating. He worked as a personal tutor and, accompanying a family to Gießen in 1839, he stayed on in Germany to study chemistry under Justus von Liebig, earning a Ph.D. in 1841.On returning to England the same year, he again considered Holy Orders but instead was attracted to Manchester to join the chemical laboratory of Lyon Playfair at the Royal Manchester Institution. Here he became involved in some of the environmental issues of the world's first industrial city (see History of Manchester). Playfair left for greener pastures in 1845 and Smith worked at making a living as an independent analytical chemist. After some initial alarming experiences, Smith refused to take on expert witness work which was a staple of consulting scientists of the day and which he saw as corrupt. Consequently, when the Alkali Inspectorate was established by the Alkali Act 1863, Smith's integrity made him the natural candidate. He held the post until his death. He is buried in the graveyard of St Paul's Church on Kersal Moor, SalfordIn 1872 Smith published the book Air and Rain: the Beginnings of a Chemical Climatology, which presents his studies of the chemistry of atmospheric precipitation. He was conferred with Honorary Membership of the Institution of Engineers and Shipbuilders in Scotland in 1884. After his death his collection of 4000 books was acquired by the library of Owens College, Manchester. They are now in the John Rylands University Library the successor of the college library.