exhibited designs for a Gothic church at the Royal Academy, where his work continued to be seen at intervals. In 1785–6 Porden was chosen to make the necessary fittings in Westminster Abbey for the Handel festival. He was also employed by the parish of St. George's, Hanover Square, and was surveyor of Lord Grosvenor's London estates. From 1790 onwards he designed a number of churches and mansions in various parts of England.
In 1804 Porden began his most important work, Eaton Hall in Cheshire for Lord Grosvenor—a palace of celebrated, if somewhat too florid, magnificence. This work occupied him till 1812. He was assisted, first by his son-in-law, Joseph Kay, and later, by B. Gummow, who built the wings in 1823–5. Besides the superintendence of the works at Eaton, he was busy with several other buildings, chiefly at Brighton, where he erected, in 1805, stables, riding-house, and tennis-court for the Prince of Wales's Pavilion; adding, during the two following years, the west front and entrance hall. In 1808 he designed Broom Hall, Fifeshire, and Eccleston church, near Chester, in 1809 and 1813. He died on 14 Sept. 1822, and was buried in St. John's Wood chapel. According to Redgrave, his end was hastened by annoyance at being superseded two years before in his employment as architect to Lord Grosvenor, to whom his work did not give entire satisfaction. Extensive alterations and additions have been made to Eaton Hall since his time.
Porden had a numerous family, all of whom died young, except two daughters; the elder of these married, in 1807, Joseph Kay (1775–1847), the architect of the new post office in Edinburgh and surveyor to Greenwich Hospital; the younger, Eleanor Anne (1797?–1825), the first wife of Sir John Franklin, is separately noticed.
[Dict. of Architecture; Redgrave's Dict. of Artists; Hicklin's Guide to Eaton Hall; private information.]
PORRETT, ROBERT (1783–1868), chemist, son of Robert Porrett, was born in London on 22 Sept. 1783. When he was eleven years of age he ‘amused himself by drawing up and writing out official papers for his father,’ who was ordnance storekeeper at the Tower of London. These productions led the war office officials to offer to keep him in the department as an assistant. He was appointed in 1795, promoted later to be chief of his department, and retired on a pension in 1850, when his services received official acknowledgment. He died on 25 Nov. 1868, unmarried. Robert Porrett Collier, lord Monkswell [q. v.], was his nephew.
Porrett was elected fellow of the Society of Antiquaries on 9 Jan. 1840 and of the Royal Society in 1848. He was an original fellow of the Chemical Society, and also a fellow of the Astronomical Society. His position and residence in the Tower led him to take an interest in antiquities. He was a recognised authority on armour, on which he contributed several papers to ‘Archæologia’ and the ‘Proceedings’ of the Society of Antiquaries.
Although he was not a professional chemist, Porrett did valuable work in experimental science. Towards the end of 1808 he found that by treating prussic acid with sulphuretted hydrogen a new acid was formed, which he termed prussous acid. For this investigation he was awarded a medal by the Society of Arts. In 1814 he discovered the qualitative composition of the acid, and showed that it was formed by the union of prussic acid and sulphur, and termed it sulphuretted chyazic acid. Its present name of sulpho-cyanic acid was given by Thomas Thomson (1773–1852) [q. v.] (Thomson's Annals of Philosophy, xii. 216), and its quantitative composition was determined in 1820 by Berzelius. In 1814 Porrett also made the important discovery of ferrocyanic acid, which he termed ferruretted chyazic acid. He showed by the electrolysis of the salts, then known as triple prussiates, and by the isolation of the acid itself, that the iron contained in the salts must be regarded as forming part of the acid, thus confirming a suggestion previously put forward by Berthollet (Kopp, Geschichte der Chemie, iv. 377). He examined the properties of the acid carefully, and showed that it can easily be oxidised by the air, Prussian blue being formed at the same time; this observation has been utilised in dyeing (Porrett in Philosophical Transactions, 1814, p. 530, and Watts, Dict. of Chemistry, ii. 227). Porrett attempted to determine the quantitative composition of prussic acid, and showed that when it is oxidised the volume of carbonic acid formed is exactly twice that of the nitrogen. But his other data are erroneous, and the problem was completely solved by Gay-Lussac shortly after. Porrett in 1813 made some interesting experiments in conjunction with Rupert Kirk and William Wilson on the extremely dangerous substance, chloride of nitrogen.
His ‘Observations on the Flame of a Candle,’ a paper written in 1816, contain important and hitherto neglected confirmation of Davy's then just published view of