Rediscovery of the Elements , Nitrogen, and the Demise of Phlogiston

Edinburgh, 4 Modern Botanic Firth of 4 Gardens " Original Forth Leith Walk (Botanic Gardens)

Rutherford's NS 0 " home Castle "".-'New" College James L. Marshall, Beta Eta /971, and National " South Bridge Virginia R. Marshall, Beta Eta 2003, Museum of Department of , University of Scotland Black's final home North Texas, Denton, TX 76203-5070, [email protected] *lkm

In the previous HEXAGON "Rediscovery" MODERN article, the life and work of UNIV of EDINBURGH (1728-1799) was introduced." As a graduate Joseph Black Building Daniel Rutherford student at the , % Building Scotland, Black discovered fixed air (carbon dioxide) and characterized magnesium as a Figure 2. Map of Edinburgh, Scotland. The chemical discoucrics of Black and Rutherford were performed at substance separate from calcium, and thus may the "Old College"in Edinburgh, which is not identified on this modern map, because it was demolished and be considered the discoverer of that calcareous replaced by buildings of the "New College,"on South Bridge (N55 56.85 W03 11.17). Rutherford, later a element. Afterwards he became professor at professor of at the University of Edinburgh, maintained the Botanic Gardens at"Leith Walk" the University of Glasgow, where he developed (see Figures 4,5); today's Royal Gardens are located 2 km west. The locations of the homes of Black and the concept of latent heat. He returned to the Rutherford are known, but they no longer exist. The modern campus is 2.7 km south of the "New Campus." University of Edinburgh in 1766 as the head of chemistry. (Figure 1). Scotland." Other students of Black attained The characterization of "malignant air." Black as a professor at Edinburgh. Upon his prominent positions at Oxford University."' Daniel Rutherford described the discovery of return to Edinburgh (Figure 2), Black turned Another of his students was Daniel Rutherford this new air in his 1772 M.D. dissertation away from fundamental research and instead (1749-1819), (Figure 3) who was the son of ("Inaugural dissertation on the air called fixed concentrated on industry and teaching. An John Rutherford (1695-1779), one of the or mephitic").' In his dissertation research, active participant in the Scottish Enlighten- founders of the Medical Institute at Rutherford "destroyed" ordinary air (i.e., ment, he was sought out by scientists through- Edinburgh.'; Daniel later became professor of removed the oxygen) by burning charcoal, can- out Europe for guidance in chemical curricula botany at the University of Edinburgh (Figures dle, or phosphorus, or by respiration with a liv- and industrial research.2" He mentored several 4-6), but never rose to the prominence of his ing mouse. In the cases where mephitic air graduate students, one of whom succeeded father John or of Joseph Black. However, while (fixed air, or carbon dioxide) was produced, he him as chair of chemistry,' Thomas Charles a student of Black, he found his mark as the removed this with alkali, following the proce- Hope (1766-1844), who first fully characterized discoverer of "malignant air," later to be known dure of his mentor Joseph Black.', Rutherford strontium, discovered in a mine in northwest as nitrogen. concluded that the remaining "malignant air"3

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I une . Ioseph Blais origItal paintinfronm which most black and white engravings are figure 4. This is a north view of the Leith Walk Gardens at the time of Rutherford, who maintained them reproduced. It was painted (ca. 1790) by Sir Henry when he became professor of botany in 1786 at the University of Edinburgh."The road in the foreground Raeburn, titled "ProfessorJoseph Black (left-right) is Leith Walk, which exists today (see map, Figure 2). The field to the right has rows of rhubarb, (1728-1799)."Courtesy, Hunterian Museum and grown for medicinal purposes; the seeds were obtainedfrom St. Petersburg, Russia. Only a tiny remnant of Art Gallerv, Unier.it' o Glaot. the original garden exists todayl (see next figure). Courtesy, Royal Botanic Garden, Edinburgh, Scotland.

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Figure 3. Lngra'ingof Lamel Ruthe rti, atter a painting by Sir , from ref o. must be "atmospheric air saturated with phlo- HOPETOUN' giston" since it "cannot be converted into 3 mephitic air by combustion." Rutherford never gave his air a specific name, but did speculate that it was "pure phlogiston united to common I i''1 1 . innk ht toal)y: I lopetotm riscent, an arc extending from Leith Walk (road) oJ a gras y-w og air" seeming to "form another species of air" of trees with benches for resting (N55 57.69 W03 11.05). Inset: Sign on fence. [authors' italics]. Rutherford was impressed with the "poiso- nous" nature of mephitic air, which lay low in from all mephitic air, is nevertheless still found resolved the issue of "mephitic air" vs. "malig- caverns and asphyxiated small animals on the to be malignant and quite similar to that which nant"air. cave floor.' He was puzzled by malignant air, is spoiled by respiration."' Hearing of Priestley's It is not known where Daniel Rutherford because when "all mephitic air had been experiments, where plants became invigorated conducted his research."' Quite possibly it was removed by caustic lixivium [alkali], what (and not "poisoned") by fixed air,' Rutherford in one of the buildings on the north side of the remains does not become in any way more realized that the "malignancy" induced by res- Physic Gardens (see map of previous HEXA- wholesome."' In another experiment, piration, combustion, or calcining was a sepa- GON publication') which included the original Rutherford noted that air "which has been rate phenomenon from the"mephitic"nature of laboratories set up by John Rutherford's med- blown through ignited coals, and then purified fixed air. Unfortunately, Rutherford never ical group." These buildings were later used by

SPRING 2015/THE HEXAGON 5 ~I '4L~J -C , Cavendish's parallel research. William Ramsay, the discoverer of the inert gases," believed that since Rutherford recognized that "malignant air" was a new substance, he "may well be credited" with the discovery of nitro- gen." However, (1731-1810; the discoverer of hydrogen)" performed some work which anticipated Rutherford's research. Six months before Rutherford's thesis was pub- -a __ VY lished, Joseph Priestley (1733-1804)' read a paper to the Royal Society relaying private

a information furnished by Cavendish. In his research, Cavendish gave a more quantitative, but less general, description of Rutherford's gas. Cavendish passed ordinary air through a 4D1, red-hot tube of charcoal, with subsequent removal of fixed air by caustic alkali. Cavendish repeated this procedure repeatedly, until no more diminution of the air was observed. Thus, he observed a reduction of 180 to 162 ounces," and he noticed that the density "differed little -e 1I 't \n A L II %1C1. from ordinary air, perhaps somewhat lighter."' It is not clear what interpretation he gave of Figure 6. The Rutherford Building in the modern Uniersity of Limb rgh (N5-)' 55.33 103) 7025) is these observations, but it appears that he, like named after Daniel Rutherford, professor of botany and keeper of the Royal Gardens at Edinburgh. Rutherford, considered the residual gas to be Rutherford is also known for inventing the maximum-minimum thermometer; he was also the uncle of the consequence of the "destruction of com- Sir (1771-1832). mon air." His work was never formally pub- lished, and he has not been generally viewed as a co-discoverer of the gas. (Cavendish later iso- lated a small quantity of inert gaseous residue from nitrogen by sparking, but he did not understand it was a new separate substance, later recognized as a new element-argon-by Ramsay and Raleigh.")

4 r Scheele's discovery of "spoiled air." Carl Wilhelm Scheele (1742-1786)' may be consid- ered to be a co-discoverer of nitrogen. He described two kinds of air, viz., "spoiled air" and "fire air" (German "verdorbene Luft" and "Feuerluft" or Swedish "skamd luft" and "elds luft," respectively.)"' His work was performed at the same time as Rutherford's, but it was not published until five years later.' (Similarly, oxy- gen was discovered by Scheele before Priestley, but the opportunistic Priestley published first.1b,,) Scheele's understanding of nitrogen was advanced beyond that of Rutherford. Instead of viewing the gas to be the product of some Ac t~ 'O1. f, ,-NC K1 (Vt I I: vague "destruction" of air, Scheele believed that "air must be composed of two different kinds of Figure 7. The cornerstone of the New College was laid on November 16, 1789, by George III. The view is elastic fluids."' If he had published promptly, northward on North Bridge. The observer's viewpoint is close to the original location of John Rutherford's there is no doubt he would be considered the Medical buildings on the north side of the Physic Gardens, i.e., where the son Daniel Rutherford probably discoverer of nitrogen. In fact, in the German performed his research on "malignantair." See the next figure for the modern appearanceof this site. Wikipedia, Scheele is considered the lone dis- (Drawing 1789, David Allan.) coverer of nitrogen; Rutherford is not men- tioned.'" Joseph Black (starting in 1766) for his teaching in 1781. This building was the one where Hope and laboratory procedures, before he moved performed his research on strontium,"" and What should the new gas be called? After into the new chemistry building which was was removed during the later construction of Rutherford's announcement' of 1772, the des- constructed in the Old University Quadrangle the New Campus at the same site (Figures 7,8). ignation "phlogisticated air" or "malignant air"

6 THE HEXAGON/SPRING 2015 an authentic member of the elements in Dalton's grand philosophy of 1808.4 A But the story is not yet finished. A major source of confusion was the large inventory of nitrogen oxides that had been described princi- pally by Priestley and Cavendish. Jons Jakob Berzelius (1779-1848), the Swedish chemical giant who seemed to be at the "center of nearly every significant scientific discovery in chem- istry," 5 thought nitrogen was a compound of oxygen with an"ammonium"radical, analogous to his idea that chlorine was a compound of oxygen with a muriatic radical." However, by 1823 Berzelius had accepted chlorine" and nitrogen as bona fide elements." But it was not until the final acceptance of Avogadro's hypothesis and the application of Gay-Lussac's Law of Combining Volumes, when Stanislao Cannizzaro (1826-1910) prepared his famous pamphlet of 1858,'' that the true nature of atmospheric nitrogen was understood. This pamphlet-which was distributed to members , : ; Ils L . c'' L , in7, :ll1t ii- L DiDl IcI ' 5 -Ui of the Karlsruhe Chemical Congress of 1960 Old College where Black and Rutherford worked, but is now actually the "Old College,"because of the and which inspired a German and a Russian New Campus further south. It presently houses the library complex of the university (Playfair Library Hall). (Lothar Meyer and Dmitri Mendeleev) to for- mulate the Periodic Table several years later '- was commonly used for the portion of the Germans use "Stickstoff" ("suffocating sub- finally established the true nature of atmos- atmosphere remaining after ordinary air had stance") and the Swedes "kvyve" ("asphyxiate") pheric nitrogen: a diatomic element, N2 . been "destroyed" by combustion and fixed air since the 1790s. The Russians transliterated the had been removed." But it was not clear French name and call the substance "a3OT." The legacy of Joseph Black. The scientific whether (a) the diminution of the atmosphere thinking of Joseph Black was so advanced that during combustion was a fundamental trans- Just what exactly is this new gas? Lavoisier's often he is regarded as one of the first in Great formation of air, a "consequence of the atmos- identification of azote as an element" did not Britain to accept Lavoisier's New Chemistry." phere becoming overcharged with phlogis- immediately settle the issue of exactly what this James R. Partington (1886-1965), the author of ton,"" or perhaps, (b) as Scheele suggested, the substance was. William Higgins (1763-1825), the comprehensive A History of Chemistry, atmosphere was composed of two distinct parts an Irish chemist who in 1784 was one of the implies" that Black was endorsing Lavoisier's that were separable. During the next two earliest antiphlogistonists and an early advo- views in Edinburgh even before 1784. However, decades, various names were proposed for the cate of the atomic theory, proposed that the a closer study of Black's life shows a more con- "phlogisticated air," including: atmosphere was indeed a mixture of gases, but servative approach. It was actually one of his (a) "mofette"-the gas escaping from a was unclear whether oxygen and nitrogen in students, Richard Lubbock (1759-1808)," who volcanic vent-used earlier by Lavoisier; 4 the atmosphere were separate substances or first vigorously advocated Lavoisier's ideas. were combined." John Lubbock called the vital portion (b) "azote"-"without life"-proposed by Dalton (1766-1844) pro- of the atmos- Guyton de Morveau, 1737-1816, who posed a clearer description of the atmosphere," phere principium sorbile (absorbable principle; which he declared consisted of discrete introduced the New Chemical Nomenclature parti- called by Lavoisier principe oxigene) and he cles."' In 1803 (Methode de Nomenclature Chimique);"' he hypothesized' that each ele- devoted his entire Dissertation in Edinburgh ment consisted of atoms of a specific weight, (1784) to this subject.' (After graduation (c) "azotic gas"-used by Cavendish;" and he gave each element its own special Lubbock became a practicing physician in (d) "nitrogene"or"nitrogen"-"niter genera- symbol (e.g., 0 for oxygen, (D for nitrogen)." Norwich, in Norfolk County, England). The first tor," created by sparking the atmosphere- Dalton was formalizing these ideas on the professor in Scotland to advocate exclusively proposed in 1790 by Jean-Antoine Chaptal atmosphere and its constituent elements dur- Lavoisier's chemistry9 actually was Black's stu- (1756-1832)," a French industrialist and ing Priestley's twilight years as Priestley contin- dent, , who became pro- popular author of science texts; and George ued to preach that phlogisiticated air (nitrogen) fessor at Glasgow in 1787, later at Edinburgh. Pearson (1751-1828), a student of Joseph was an undefinable substance containing The cautious Black believed there were too Black who translated Mithode de Nomen- dephlogisticated air (oxygen), possibly even a many unanswered questions-with a "scheme clature Chimique" into English" in 1794. compound of dephlogisticated air and inflam- so dependent upon a few key experiments..." 2 In Lavoisier's 1789 Trait,' nitrogen was rec- mable air (hydrogen)." But Priestley was now he was worried that "should these experiments ognized as an element for the first time; he list- virtually alone with his antiquated philosophy, be overturned the entire structure was under- ed it as "azote." The French chemical literature and when he died (1804) there were no mined."" With the backdrop of the Scottish has retained "azote"; but with Pearson's trans- remaining significant adherents to the philoso- Enlightenment, the role of Black was to create lation of Nomenclature Chimique, "nitrogen" phy of phlogiston." Nitrogen had joined the the cultural environment at Edinburgh which passed into the English vocabulary. The ranks of the true elements and was included as allowed free debate, tolerating all views.

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Student societies flourished that nurtured this 5. A. G. Fraser, The Building of Old College. intellectual freedom, giving rise to "one of the Adam, Playfair & University of Edinburgh, earliest sustained debates over the new chem- 1989, Edinburgh University Press, 27-50. istry outside Paris."" The conversion of Black 6. W. Ramsay, The Gases of the Atmosphere, was gradual. In the end, he was convinced not 1915, Macmillan, 41. by the students' youthful exuberance which he 7. J. Priestley, Phil. Trans., 1772, 62, 147-256. fostered, but ultimately by the wealth of their data and cogent arguments. In 1790 he finally 8. J. R. Partington, A History of Chemistry, proclaimed his endorsement of the New Vol. III, 1962, Macmillan, (a) 222; (b) 263; Chemistry in a letter to Lavoisier," which was (c) 318; (d) 416-424; (e) 481; (f) 489; (g) 50; published in the French journal Annales de (h) 627; (i) 694; (j) 738; (k) 755-822. Chimie." 9. C. W. Scheele, Chemische Abhandlung con der Luft und dem Feuer ("Chemical Treatise Acknowledgments. of Air and Fire"), 1777, Upsala und Leipzig, The assistance of Robert G. W. Anderson, Verlegt von Magn. Swederus, Buchhindler. Emeritus Fellow, Clare Hall, Cambridge 10. http://de.wikipedia.org/wiki/Stickstoff University, and author of refs 2 and 4b, is grate- 11. T. Thomson, History of Chemistry, 1830, fully acknowledged. H. Colburn and R. Bentley, Vol. 1, 346. References. 12. A.-L. Lavoisier, Tmitc EIrnentairede Chimie, 1789, Paris. 1. James L. Marshall and Virginia R. Marshall, 13. R. E. Schofield, The Enlightened The HEXAGON of Alpha Chi Sigma, (a) 2002, Joseph Priestley. A Study of His Life and Work from 93(3), 42-47; (b) 2005, 96(1), 8-13; (c) 2005, 1773 to 1804, 2004, Pennsylvania State 96(2), 28-33; (d) 2007, 98(1), 3-9; (e) 2007, 98(4), 70-76; (f) 2012, 103(3), 36-41; (g) University Press, University Park, PA, 2014, 105(3), 40-45. 361-365. 14. John Dalton, 2. R. G. W. Anderson, The Correspondence of A New System of Chemical Philosophy, 1808, Manchester. Joseph Black,Vol.1, 2012, Ashgate Publishers, (a) 36-38; (b) 40. 15. P. B. Moore, The Mineralogical Record, 1988, 3. DissertationInauguralis de arefixo, aut mephitico 19, 293-295. ("Inaugural dissertation on the air called 16. J. R. Partington, A History of Cheniistr, fixed or mephitic"), University of Edinburgh, Vol. IV, Macmillan, 1962, 156-166. 1772. A translation of Rutherford's disserta- 17. S. Cannizzaro, Nuovo Cimento, 1858, 7, tion from the original Latin appears in 321-366. L. Dobbin, J. Chem. Ed., 1935, 12(8), 370-375. 18. A. Grant, The Story of the University of 4. R. G. W. Anderson, (a) private communica- Edinburgh during its FirstThree Hundred tion; (b) The Playfair Collection and the Years,Vol. 2, 1884, Cambridge University Teaching of Chemistry at the University of Press. Edinburgh 1713-1858, 1978, Royal Scottish 19. C. E. Perrin, Ambix, 1982, 29(3), 141-195. Museum Studies, 20-23. 20. Letter of Black to Lavoisier, Ann. chim., 1791, 8, 225-229.

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