TKAXSACTIONS OF SECTION n. 669 



in the subject for some tweuty-tbree years (1774-1796) iu bis Scbool of Practical 

 Chemistry in Greek Street, Soho, Loadou. Towards the end of his cai-eer as a 

 teacher he was instrumental in spreading a knovvledore of the new (anti- 

 phlogistouist) system of chemistry. The ' Society for Philosophical Experiments 

 and Conversations' met in his laboratory (1794 e^ seq.). Before this Society, 

 which included politicians, lawyers, and physicians of high standing in London, 

 Higgins demonstrated the experiments which formed the basis of the new 

 chemistry. 



His practical work, which is extensive, was carried out with extraordinary 

 attention to detail. As technical chemist he did work on cements, on soap, and 

 on glass. In the West Indies, where he went on the invitation of a committee 

 of the Jamaica House of Assembly, he investigated the manufacture of musco- 

 vado sugar and rum (1797-1802). la pure chemistry he carried out one large 

 research, and made a number of minor discovp~ies, including that of the musical 

 note which may be produced when a jet of hydrogen burn&in air. 



'The Experiments and Observations concerning Acetous Acid, '&c. (1786), is 

 an elaborate investigation into acetic acid and acetates. Higgins describes the 

 preparation of pure acetic acid, and of the acetates of calcium, potassium, mag- 

 nesium, ammonium, and lead. Having investigated the effect of heat upon these 

 substances, he arrived at a definite conclusion regarding the constitution of acetic 

 acid — virtually, that it consists of carbon dioxide (' fixable air ') and methane 

 (' heavy inflammable air '). 



Distilling ammonium acetate, he obtained acetamide. He purified it carefully 

 by 'five sublimations,' and in a detailed account of its properties gives the 

 melting-point as 170"^ F. instead of 177° F. 



In the ' Philosophical Essay concerning Light ' (1776) Higgins gives reasons 

 for rejecting the emission theory of light and for adopting an undulatory theory, 

 but on this question be afterwards changed his mind. He adapted the Newtonian 

 atomic theory to the purposes of chemistry, and supposed that acid and alkali 

 combine atom with atom. In this way he accounted for the fact, which he proved 

 by an ingenious experiment, that ammonia and hydrochloric acid gases combine 

 in single definite proportion. 



William Higgins (d. 1825) was trained in chemistry by his uncle Bryan 

 Higgins. He assisted Dr. Beddoes in the teaching of chemistry at Oxford (1787), 

 and he acted as chemist to the Apothecaries' Hall of Ireland (1791-1795), and 

 then to the Royal Dublin Society (1795-1825). He carried out experimental 

 work on bleaching for the Irish Linen Board. A Fellow of the Royal Irish 

 Academy, he acted as a member of its Council for many years. In 1806 lie was 

 elected to the Royal Society of London. He published three books : (1) 'A Com- 

 parative View of the Phlogistic and Antiphlogistic Theories ' (1789) ; (2) ' An 

 Essay on the Theory and Practice of Bleaching, wherein the Sulphuret of Lime 

 is recommended as a Substitute for Potash ' (1799) ; (3) ' Experiments and Obser- 

 vations on the Atomic Theory and Electrical Phenomena' (1814V 



Having become a Lavoisierian in 1785, Higgins was the first to write against 

 phlogiston in the English language. Written expressly in reply to Kirwan's 

 essay on the .«ubject, the 'Comparative View' was published in the year 

 1789, just when there was a revulsion of feeling in England in favour of 

 phlogiston. 



He made the important observations that at the ordinary temperature — 



(1) Quicklime and dry hydrochloric acid gas do not combine (1789). 



(2) Dry nitric oxide and sulphuretted hydrogen do not interact (1814). 



(3) Phosphorus does not act with undiluted oxygen as it does with the 



oxygen of the air (1814). 



Throughout the ' Comparative View' Higgins makes use of the atomic theory. 

 Ho believed firmly that combination occurs in definite proportions, and he sup- 

 posed that in the first place combination occurs atom with-atom. The molecule of 

 water he regarded virtually as OH. 



in the case of water, sulphuretted hydrogen, and sulphur dioxide he attempted 



