.NIEL RUTHERFORD and the
DISCOVERY of NITROGEN' MARY ELVIRA WEEKS The University of Kansas, Lawrence, Kansas From Rommy'r "The Gorrr of rhr .tlmor$hna"
Although the statement that nitrogen was discovered in 1772 by Daniel Rutherford appears in most histories of chemistry, this Scottish scientist has remained almost unknown to chemists. Nevertheless, the life story and personal character of Dr. Rutherford emerge from the correspondeme of his distinguished nephew, Sir Walter Scott, in a most pleasing manner. Both Dr. Rutherford and his father smed as physicians to the Scott family, and the great novelist's allusions to them combine admiratio* sincere affection, and pardonable family pride. Dr. Rutherford served as firofessor of botany at the University of Edinburgh from 1786 to 1819, and was thus contemporary with Joseph Black, Charles Hope, and John Robison. He invented a n ingeniozw maximum and 1?zz'nimum thermometer which is described in many modern textbooks of physics. The tragic circumstances surrounding his sudden death were described by Sir Walter in numerous letters to members of his family. I n his doctor's thesis Rutherford made a clear distinction between nitrogen and carbon dioxide which most of his contemporaries had failed to observe. +Sir Henry Cavendish, however, had made this distinction somewhat earlier, but had failed to publish his results. The names of Priestley and Scheele are also intimately connected with the discovery of nitrogen.
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HE correspondence of Sir Walter Scott, his family genealogy, and the ten-volume biography by his son-in-law, J. G. Lockhart, contain frequent allusions to Scott's grandfather, Dr. John Rutherford, one of the founders of the medical school at the University of Edinburgh, and to his uncle, Dr. Daniel Rutherford, who is usually regarded as the discoverer of the element nitrogen. In the genealogy of the Scott family one may read:
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* Presented before the Division of History of Chemistry a t the Washington meeting of the American Chemical Scciety, March 28. 1933.
DANIELR U T H E ~ O R1749-1819 D. Scottish physician, botanist, and chemist. Discoverer of nitrogen. Professor of hotanv a t Edinbureh. President of the ~o;al College of ?'hysiciaus of Edinburgh. By his first wife. Jean ,%inton, Professor John Rutherford had a son. John, who died young, and a daughter Anne, who marriedt Walter Scott, Bart. He married, secondly, on the 9th August, 1743. Anne M'Kay, by whom he had five sons and three daughters. Daniel Rntherford, second son of Professor John Rutberford, was born on 3rd November, 1749. Prosecuting medical studies a t the University df Edinburgh, he early discovered the existence of a gaseous fluid, now known as nitrogen gas. .I
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S i r Walter Scott gave some of +hi 'same facts in the following passage from his autobiography:
I n [April, 17581 my father married Anne Rutherford, eldest daughter of Dr. John Rutherford, professor of medicine in the University of Edinburgh. He was one of those pupils of Boerhaave t o whom the school of medicine in our northern metropolis owes its rise, and a man distinguished for professional talent, for lively wit, and for literary acquirements. Dr. Rutherford was tvdce married. His first wife, of whom my mother is the sole surviving child, was a daughter of Sir John Swinton of Swinton, a family which produced many distinguished warriors during the middle ages, and which, for antiquity and honourable alliances, may rank with any in Britain. My grandfather's second wife was Miss Mackay, by w h o d e had a second family, of whom are now [1808] alive, Dr. Daniel Rutherford, professor of botany in the University of Edinburgh, and Misses Janet and Christian Rntherford, amiable and accomplished women.
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As might be expected, the Rutherfords, both father and son, served as physicians to the Scott family. When Sir Walter was only eighteen months old, his right leg became paralyzed, and, after the best physicians had failed in their attempts to restore the use of it, his grandfather, Dr. John Rutherford, had him sent
t A facsimile of the marriage contract is t o be found in ref. 4.
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ROGERS,C., "Genealogical memoirs of the family of Sir Walter Scott, Bart. of Abbotsford," Roy. Historical Soc., London, 1877, pp. Iv-lviii. L o c ~ n h n r J. . G., "Memoirs of the life of Sir Walter Scott," Adam & Charles Black, Edinhurgh, 1862, vol. 1, p. 14.
to live in the co~ntry.~8' During a serious illness in later life, Scott "submitted without a murmur to the severe disciplme prescribed by his affectionate physician [Dr. Daniel Rutherford] . . "6 John Rutherford was born in the Manse of Yarrow, Scotland on August 1, 1695, was educated a t the grammar school at Selkirk, and studied anatomy, surgery, and materia medica in London and later in Leyden under Boerhaave. After receiving his medical degree from the University of Rheims in 1719, he went to Edinburgh to engage in private practice. In November, 1724, he applied, with three other members of the College of Physicians, for the keeping of the college garden, which had fallen into disuse. With the consent of the town council, the four physicians raised medicinal plants there and, in order to prepare drugs for the apothecaries' shops, set up a chemical laboratory at their own expense. Two years later Dr. Rutherford was appointed Professor of the Practice of Medicine in the medical school which he had helped to found. He used Boerhaave's "Aphorismi de Cognoscendis et Curandis Morbis" as a textbook, and for many years delivered clinical lectures in the Edinburgh Inkmary. He resigned in 1765, and died in 1779 a t the axe of einbty-
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Dutch physician, anatomist, chemist, and hotanist. The Edinburgh Medical School was founded by pupils of Bwrhaave while he was still in his mime. Tohn Rutherford, father of Daniel ~utheriord',was ol;e of his devoted disciples.
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"ROGERS,ref. 1, p. lii. "GRANT,SIR ALEXANDER, "The story of the University of Edinburgh during its 6rst three hundred years, Longmans, Green & Ca.. London. 1884, vol. 1, pp. 308-15.
According to Florence MacCunn, both Sir Walter Scott and his mother inherited their "homely features and look of.good-tempered shrewdness" from "old Dr. Rutherford, whose homely, heavy, sensible face hangs in the rooms of the Edinburgh College of physician^."^ According to Lockhart, Dr. Daniel Rutherford "inherited much of the general accomplishments, as well as the professional reputation, of his father."P He was keenly interested in the classics, in English literature, and in mathematics, and his graduation thesis, like that of his celebrated professor, Dr. Joseph Black, clearly revealed the existence of a new gas. Just as Black's dissertation, "De humore acido a cibis orto, et magnesia alba,"* published on June 11, 1754, had contained the discovery of carbon dioxide, Rutherford's thesis, "Dissertutw inauguralis de aere, fix0 dido aut mephitico,"' dated September 12, 1772, made clear the existence of nitrogen (phlogisticated air) as distinct from carbon dioxide (6xed air). Although Stephen Hales had prepared nitrogen by absorbing the oxygen from a conlined volume of atmospheric air, he had failed to recognize it as a new subi r Henry Cavendish was evidently the first stance." S person to distinmish nitrocen from other kinds of sufrocatinn incombkible nas& but he had failed to publish hisresults. In a paper marked in his handwriting "communicated to Dr. Priestley," he had written: I am not certain what it is which Dr. P[riestleyl means by mephitic air, though from some circumstances I guess that what he sneaks of. . .was that to which Dr. Black has eiven the name of fixedair. Thenatural meaning of me~hiticairijany air which suffocates animal, (& this is what Dr. Prwst1r.y seem, to mean by the words), but in all probability there are many kinds of air which possess thii property. I - a m sure there are 2, namely, fixed air, &common air in whi6h candles have burnt, or which has passed thro' the fire. Air which has passed thro' a charcoal ike contains a great deal of fixed air, which is generated from the charcoal. hut it consists urincioallv . . of common air. which has 4-Tercd a change in its nature from the fir?. As I formerly made a n cvperimcnt on this subject, which retms to contain rome new circumstances, I will here set i t do-. I transferd some common air out of one receiver through burning charcoal into a 2nd receiver by means of a bent pipe, the middle of which was filled with powdered charcoal & heated red hot, both receivers being inverted into vessels of water, & the 2nd receiver being full of water, so that no air could get into i t but what came out of the first receiver & passed through the charcoal. The quant. air driven out of the ikst receiver was 180 oz. measures, that driven into the 2nd receiver was 190 oz. measures. In order t o see whether any of this was fixed air, some sope leys was mixed with the water in the hason, into which the mouth of this 2nd receiver was immersed; i t was thereby reduced t o 166 oz..** so that 24 oz. meas. were absorbed bv the sone . levs. . dl of wgch wc may conclude to be fixed air produkd from thecharcanl; therefore 14 oz. of common air r e r * absorbed by the fumes of rhc 8 MACCUNN, "Sir Walter Scott's friends," Wm. Blackwood & Sons, Edinburgh and London, 1910, p. 12. ref. 2, vol. 1, p. 188. LOCK~ART, * The acid arising from food, and magnesia alba. t Inaugural dissertation on the air called fixed or mephitic. l o CLARK-KENNEDY, "Stephen Hales, D.D., F.R.S.," University Press, Cambridge, 1929, pp. 101-10. ** The number 168 eiven in the British Association Renorts is evidently a misprint. v
In the same paper Priestley stated: Air thus diminished by the fumes of burning charcoal not only extinguishes flame, hut is in the highest degree noxious to animals; it makes no effervescencewith nitrous air, and is incapable of being diminished any farther by the fumes of more charcoal, by a mixture of iron filings and brimstone, or by any other cause of the diminution of air that I am acquainted with. This ohservation, which respects all other kinds of diminished air, proves that Dr. Hales was mistaken in his notion of the absorption of air in those circumstances in which he observed it. For he supposed that the remainder was, in all cases, of the same nature with that which had been absorbed, and that the operation of the same cause would not have failed to produce a farther diminution; whereas all my observations not only shew that air, which has once been fully diminished by any cause whatever, is not only incapable of any farther diminution, either from the same or from any other cause, but that it has likewise acquired new properties, most remarkably different from those which it had before, andthat they arc,ina great measure, thesame inall the cases. . . . I z
Scottish novelist and poet. His writings contain many interesting allusions to his unclc. Dr. Daniel Rutheriord. Scott's circle of friends included Dr. William Hyde Wollaston, Sir David Brewster. Dr. John Davy, Sir Humphry Davy, and Joseph Black.
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burning charcoal, agreeable to what Dr. Hales and others have observed, that all burning bodies absorb air. . . "
With characteristic thoroughness Cavendish had passed the 166 ounces of residual air hack again through fresh burning charcoal into another receiver. After another treatment with the soap lye there remained llj2 ounces of a gas which he described as follows: The specific gravity of this air was fo&d to differ very little from that of common air; of the two it seemed rather lighter. I t extinguished flame, & rendered common air unfit for making hodies burn, in the same manner as fixed air, hut in a less degree. . . ."
In a paper read before the Royal Society in March, 1772 (six months before Dr. Rutherford's thesis was published), Priestley mentioned these experiments, hut failed to record Cavendish's clear interpretation of them.
Priestley also observed that "lime-water never became turbid by the calcination of metals over it," and that "when this process was made in quicksilver, the air was diminished only one-fifth; and upon water being admitted to it, no more was abs~rbed."'~He stated that this "air in which candles, or brimstone, had burned out . . . is rather lighter than common air."L2 Thus Priestley recognized, even at this early date, some of the most important properties of the gas now known as nitrogen. The only copy of Rutherford's thesis which Sir William Ramsay was able to find is in the British Museum. Although Ramsay stated in the first edition of "The Gases of the Atmosphere" that this dissertation "precedes Priestley's and Scheele's writings by a year or two," he corrected this in the second edition to read: " . . . Priestley had nearly anticbated Rutherford, and indeed, he speculated on the nature of the residual gas, left after combustion and absorption of the fixed air pr~duced."'~Although Rutherford referred in his thesis to Priestley's experiments on the effect of vegetation on the atmosphere, he was evidently unfamiliar with those on n i t r ~ g e n . ' ~ J ~ Dr. Black had noticed that when a carbonaceous substance is burned in air in such a manner that the fixed air can he absorbed in caustic alkali, a portion of the air remains. He had therefore assigned to his student Daniel Rutherford, the investigation of this residual air in partial fulfilment of the requirements for the degree of doctor of medicine. The dissertation begins with an appropriate quotation from Lucretius and a review of the researches of Black and of Cavendish on fixed air. Rutherford then described his own experiments in which he had found that a mouse, left in a confined volume of atmospheric air until i t died, had consumed one-tenth of the air, and that treatment of the remaining air with alkali had caused it to lose one-eleventh of its volume. He found
The Honourable Mr. Cavendish favoured me [said he] with an account of some experiments of his, in which a quantity of common air was reduced from 180 to 162 ounce measures, by passing through a red-hot iron tube filled with the dust of charcoal. This diminution he ascribed to such a destruction of common air as Dr. Hales imagined to he the consequence of burning. Mr. Cavendish also observed, that there had been a generation of fixed air in this process, hut that it was absorbed hy sope l e y ~ . 1 ~-
" HARCOURT, "Presidential
address." Brit. Assoc. Reports, weer 9.3-68 (Aue.. 1839). A reorint of Cavendish's . . on nitrogen . is included.'' . ' l P x r e s ~ z e "Observations ~, on different kinds of air," Phil. Trans.,62, 147-256 (1772). Read Mar. 5, 12. 19. 26 (1772).
13 RA~sAY, "The gases of the atmosphere," 1st ed., Macmillan & Co., Loydnn, 1896, p. 62; ibid., 2nd ed., 1915, p. 63. LEE, Dictionary of national biography," The Macmillan Co., New York City, 1897, vol. 50, pp. 5-6. Article on Daniel Rutherford by B. B. Woodward. RAMSAY, ref. 13.2nd ed.. pp. 62-8.
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Rutherford added that he was unable to state with certainty anything regarding the composition of the new mephitic air nor to explain its inability to support life. He helieved, however, that it was possibly generated from the food, and expelled as a waste product from the blood by means of the lungs.'4 Certain experiments [said he] appear t o show. . . that it consists of atmospheric air in union with phlogistic material: for it is never produced except from bodies which abound in i d a m rnable parts; the phlogiston ever appears to be taken up by other bodies, and is hence of value in reducing the cakes of metals. I say from phlogistic material, because as already mentioned, pure phlogiston, in combination with common air, can he seen to yield another kind of air [hydrogen] . .IS
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nritish clermman, Lirrlr~gist,rhemist, and irtventcr. His most impurtxnt rcsrarclws were on blw,d,prrssure. circulation of sap, rrspiritlC"IC >"411 CLUSe.
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Scott once paid the following tribute to his uncle: "Dr. Rutherford was a very ingenious as well as an excellent man, more of a gentleman than his profession too often are, for he could not take the back-stairs mode of rising in it, otherwise he might have been much more wealthy. . . "30 This kindly Scottish physician is remembered today for hismaximum and minimum thermometer and for the brilliant research in which he clearly distinguished between carbon dioxide .. ana* nluogen.*-'aa 3"
LOCKHART, ref. 2. vol. 6, pp. 164-8. (Letter of Sir Walter to his brother, Thomas Scott.) 88 WEEKS, "The discovery of the elements. IV, Three important ga?es." J. CHEM.Eouc., 9, 219-21 (Feh., 1932). a @ " D RUTHERPORD ~~ iiher die mephitische Luft," Crells' Neuesten Entdeckuugen in der Chemie, Weygandsche Buchhandlung, Leipzig, 1784, vol. 12, pp. 187-96.
