Robert Porrett Explained

Robert Porrett (1783–1868) was an English amateur chemist and antiquary.

Life

The son of Robert Porrett, ordnance storekeeper at the Tower of London, he was born in London on 22 September 1783. He began work in his father's 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 November 1868, unmarried. Robert Collier, 1st Baron Monkswell was his nephew.^[1]

Works

Porrett was elected Fellow of the Society of Antiquaries of London on 9 January 1840, and Fellow of the Royal Society in 1848. He was an original fellow of the Chemical Society, and also a Fellow of the Royal Astronomical Society. He was an authority on armour, on which he contributed several papers to Archæologia and the Proceedings of the Society of Antiquaries.^[1] His subordinate at the Tower, John Hewitt, was encouraged to take an interest in the national collection of arms and armour there, and produced a pioneering guide.^[2]

Chemist

In chemistry, towards the end of 1808, Porret found that by treating prussic acid with sulphuretted hydrogen a new acid was formed, which he first termed "prussous acid" (now: thiocyanic acid, HSCN).^[3] 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".^{[4] [5]} The later name "sulphocyanic acid" was given by Thomas Thomson,^[6] and its quantitative composition was determined in 1820 by Berzelius.^{[1] [7]}

In 1814 Porrett also made the discovery of ferrocyanic acid, which he termed "ferruretted chyazic acid".^[8] 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 Claude Louis Berthollet.^[9] He examined the properties of the acid, and showed that it can easily be oxidised by the air, Prussian blue being formed at the same time; this observation was later utilised in dyeing.^[1]

Porrett attempted to determine the quantitative composition of prussic acid: he showed that when it is oxidised the volume of carbonic acid formed is exactly twice that of nitrogen, but his other data were erroneous. The problem was solved shortly after by Joseph Louis Gay-Lussac.^[10] Porrett in 1813 made experiments with Rupert Kirk and William Wilson on the dangerous substance chloride of nitrogen.^{[1] [11]}

His Observations on the Flame of a Candle (1817) supported Humphry Davy's view of the structure of flames.^[12] According to Porrett, the light is mainly due to free carbon formed in the flame by the decomposition of hydrocarbons.^[1]

Physicist

Porrett's contribution to physics was the discovery of electric endosmosis in 1814.^{[13] [14]} The phenomenon had, according to Gustav Heinrich Wiedemann,^[15] been observed previously by the German scientist Ferdinand Friedrich Reuss (18 February 1778 (Tübingen, Germany) – 14 April 1852 (Stuttgart, Germany)),^{[16] [17]} but Porrett's discovery was independent, and the phenomenon for a period went in Germany by his name.^[1]

Publications

The following is a list of Porrett's scientific papers:^[1]

• In the Transactions of the Society of Arts: 'A Memoir on the Prussic Acid' (1809, xxvii. 89–103).

In Nicholson's Journal:

• 'On the Prussic and Prussous Acids' (1810, xxv. 344).
• 'On the Combination of Chlorine with Oil of Turpentine' (1812, xxxiii. 194).
• 'On the Explosive Compound of Chlorine and Azote' (with R. Kirk and W. Wilson) (1813, xxxiv. 276).

In Philosophical Transactions:

• 'On the Nature of the Salts termed Triple Prussiates, and on Acids formed by the Union of certain Bodies with the Elements of Prussic Acid' (6 June 1814, p. 527).
• 'Further Analytical Data on the Constitution of Ferruretted Chyazic and Sulphuretted Chyazic Acids,' &c. (22 Feb. 1815).

In Thomson's Annals of Philosophy:

• 'Curious Galvanic Experiments' (1816, viii. 74).
• 'Observations on the Flame of a Candle' (viii. 337).
• 'On the Triple Prussiate of Potash' (1818, xii. 214).
• 'On the Anthrazothion of Von Grotthuss, and on Sulphuretted Chyazic Acid' (1819, xiii. 356).
• 'On Ferrochyazate of Potash and the Atomic Weight of Iron' (1819, xiv. 295).

In the Chemical Society's Memoirs:

• 'On the Chemical Composition of Gun-Cotton' (in conjunction with E. Teschemacher) (1846, iii. 258).
• 'On the Existence of a new Alkali in Gun-Cotton' (iii. 287).

References

Attribution

Notes and References

1. Porrett, Robert.
2. http://www.royalarmouries.org/collections/history-of-the-collection/early-scholars/john-hewitt Royal Armouries page, John Hewitt.
3. Porrett . R. Jr. . Memoir on the prussic acid . Transactions of the Society of Arts . 1809 . 27 . 89–103 .
4. Porrett . Robert Jr. . On the nature of the salts termed triple prussiates, and on acids formed by the union of certain bodies with the elements of prussic acid . Philosophical Transactions of the Royal Society of London . 1814 . 104 . 527–556 . 10.1098/rstl.1814.0027 . free . Sulphuretted chyazic acid is discussed on pp. 541–542.
5. The name "chyazic" was an acronym of cyanic acid's component elements: Chyazic = C[arbon] + HY[drogen] + AZ[ote] + ic, where azote is the French word for nitrogen. See: Book: Kopp . Hermann . Geschichte der Chemie . History of Chemistry . 1847 . Friedrich Vieweg und Sohn . Braunschweig, (Germany) . 4 . 377 . German. From p. 377: "Diese Säure nannte er Ferruretted-Chyazic-Acid, um ihre Bestandtheile zu bezeichnen (aus C[arbon], hy[drogen], az[ot] zusammengesetzt)." (He named this acid "ferruretted chyazic acid" in order to designate its composition, consisting of C[arbon], hy[drogen], az[ote].)
6. Book: Thomson . Thomas . A System of Chemistry, in Four Volumes . 1817 . Baldwin, Cradock, and Joy . London, England . 2 . 290 . 5th .
7. See:
   • Berzelius . Jacob . Om sammansättningen af svafvelhaltiga blåsyrade salter, samt om Selenhaltigt blåsyradt kali . Kongliga Vetenskaps Academiens Nya Handlingar (New Proceedings of the Royal Academy of Science) . 1820 . 8 . 82–99 . On the composition of sulfur-containing cyanide salts, together with the potassium [salt of] selenium-containing cyanide . Swedish.
   • Berzelius . Jacob . Ueber die Zusammensetzung der schwefelhaltigen blausauren Salze . Journal für Chemie und Physik . 1821 . 31 . 42–60 . On the composition of sulfur-containing cyanide salts . German.
8. (Porrett, 1814), pp. 532–541.
9. (Kopp, 1847), p. 377. From p. 377: "Die von Berthollet bereits angedeutete Ansicht, die Blausäure werde durch Verbindung mit oxydirtem Eisen zu einer stärkeren Säure, wurde von Robert Porrett wieder aufgenommen, von welchem die Schriften der Royal Society zu London für 1814 und 1815 zwei Abhandlungen über diesen Gegenstand enthalten." (The idea [that had] already been suggested by Berthollet – [namely, that] hydrogen cyanide would become a stronger acid by bonding to oxydized iron – was adopted by Robert Porrett, from whom the Philosophical Transactions of the Royal Society of London of 1814 and 1815 contain two articles on this subject.)
10. Gay-Lussac, J. L. . 1815. Recherche sur l'acide prussique. Research on prussic acid. Annales de Chimie. 95. 136–231.
11. Porrett . R. Jr. . Wilson . W. . Kirk . Rupert . On the explosive compound of chlorine and azote . Journal of Natural Philosophy, Chemistry, and the Arts . April 1813 . 34 . 276–290 . 2nd series.
12. Porrett . R. Jr. . Observations on the flame of a candle . Annals of Philosophy . May 1817 . 9 . 5 . 337–341 .
13. Porrett . R. Jr. . Curious galvanic experiments . Annals of Philosophy . 1816 . 8 . 74–76 .
14. Biscombe . Christian J.C. . The discovery of electrokinetic phenomena: setting the record straight . Angewandte Chemie International Edition . 2017 . 56 . 29 . 8338–8340. 10.1002/anie.201608536 . 27902877 . free . 11343/292176 . free . ; see p. 8339. Available at: Wiley.com
15. Book: Wiedemann . Gustav . Die Lehre vom Galvanismus und Elektromagnetismus … . The Theory of Galvanism and Electromagnetism … . 1861 . Friedrich Vieweg und Sohn . Braunschweig, (Germany) . 1 . 376 . German.
16. Reuss . F. F. . Notice sur un nouvel effet de l'électricité galvanique . Mémoires de la Société Impériale des Naturalistes de Moscou . 1809 . 2 . 327–337 . Notice of a new effect of galvanic electricity . French.
17. (Biscombe, 2017)