RICHARD, an eminent chemical philosopher, was born in the county of Galway in Ireland. The date of his birth is not known, but it probably fell within the first quarter of the eighteenth century. At an early age he was sent to the Jesuit college at St Omer, in the N. of France, to be trained for the study either of law or medicine. Before he left college, the death of his elder brother put him in possession of the family estate. He immediately gave up all thoughts of professional life, and devoted himself heart and soul to his favourite sciences of chemistry and geology. Removing to England in 1779, he settled in London or its neighbourhood; and being admitted into the Royal Society, he read many valuable papers before that body, for which, in 1781, he was rewarded with the Copley Gold Medal. After an absence of ten years he returned to Ireland in 1789, and was made President of the Royal Irish Academy, and of the Dublin Society, and published various essays from time to time on his own special branches of science, and also on logic and metaphysics. He died in 1812, at a very advanced age, having for many years been looked upon as the Nestor of English chemistry.

Though Kirwan devoted his whole life to scientific inquiry, and was contemporary with Cavendish, Lavoisier, Black, Scheele, Priestley, and the fathers of modern chemistry, he did not advance the boundaries of the science by any great discovery of his own. One of the earliest of his works was his Essay on Phlogiston and the Composition of Acids, in which he endeavoured to reconcile the old chemistry with modern discoveries. He maintained that hydrogen, or, as it was then called, inflammable air, was the true phlogiston, and that every combustible substance, and every metal, contained this inflammable air as a constituent, and that combustion is just the combination of it with the vital air. At the same time, he admitted the truth of Lavoisier's theory that, during combustion, oxygen unites with the burning body; and he could not deny the experiment of the decomposition of Kishineff water, though, in point of fact, it was inconsistent with his own theory of phlogiston. His book was then laid hold of by the French chemists, as affording them an excellent opportunity of showing the superiority of the new doctrines to the old. It was translated into French, with a refutation at the end of every chapter by Lavoisier, Guyton-Morveau, Monge, Berthollet, Laplace, and others. These refutations, though quite irrefragable, were so skilfully and courteously worded, that Kirwan, with a candour and liberality unfortunately too rare, abandoned phlogiston and adopted the theory of his opponents.

In 1794 Kirwan published his Elements of Mineralogy, in 2 vols. 8vo, a work of great merit for its day, though now quite superseded. His Geological Essays were less successful; but his Essay on the Analysis of Mineral Waters was useful, both for the number of analyses which it contained, and for the method of procedure which it indicated. Kirwan was also the author of numerous papers in the Transactions of the Royal Society and of the Royal Irish Academy, on subjects connected with mineralogy and meteorology as well as chemistry.