H. Cassebaum, Magdeburg, East Germany
Scheele's Priority for
ID.D. R.l and J. A. Schufle New Mexico Highlands University Las Vegas, 87701
I
Discovery of Oxygen
During the year 1974 we celebrated the 2M)th anniversary of the discovery of oxygen by Joseph Priestley. But in 1962 Partington (1, 2) pointed out, and Schufle (3, 4) reemphasized somewhat later, that Torbern Bergman had published Scheele's discovery of oxygen a t a date earlier than Priestley's puhlication. Now some recent developments have thrown these conclusions into doubt. Recently Cassebaum (5-71 has been reinvestigating the whole question of the discovery of oxygen, and has been pointing out the seemingly undisputed priority of Scheele for this discovery. Discovery of Oxygen Defined
In discussing an event as important as the discovery of oxygen in the history of chemistry we find there are several aspects to the process of discovery. We might set forth the following five steps a s critical to the discovery, and the understanding of what was discovered 1) Preparation and collection of the pure gas. 2) Identification of this gas with that part of the atmosphere
Bergman's apparatus to accompany
Nova ActaUpsala. Vol 2. 1775.
Concerning the Date of Communication of Discovery to Other Scientists
search on hraunstein iMnOz). The latter was considerably reduced in length by Bergman before publication. In a letter to Bergman on January 12, 1776, Scheele defended the puhlication of his book "Air and Fire." "I have here the opportunity to reiterate the greatest part of my researches concerning air and fire. I have put them in order and since they were brought out in a somewhat scattered way, I have given them to Herr Swederus by whom they will be published in German" (10). But there is no direct evidence that Scheele put anything about his discovery of oxygen in the original manuscript of his braunstein article, which was presented to the Swedish Academv on Januarv 12. 1774 and nublished on Julv 1. 1774 (fi, -7: Also from his acid of arsenic article of 1774 16,' 12) we learn that a t this time Scheele still had nothine to report about oxygen. Partington (1, 2! and Schufle 13, 4.1 have published the fact that Bergman included a summary of Scheele's preparation of oxygen by heating mercury calx in his "Dissertation on Elective Attractions" which appeared in Noua Acta Upsala, Vol. 2, 1775 113a:. Partington further stated ( 1 1 that the journal could have been in print on June 16, 1774, three months before Priestley made his discovery of oxygen in August 1774. However, some other evidence now seems to indicate that Bergman did not learn about Scheele's discovery of oxygen until early in 1776, when he obtained a copy of Scheele's hook "Air and Fire," and wrote a Foreword for the hook. He then, in our hypothesis, inserted his summary of Scheele's discovery of oxygen into his "Attractions" Article in Noua Acta, which was still on the press, a t the last minute, sometime about April or May 1776, and it was then published. We will discuss this hypothesis later. In the latter half of 1775 Bergman's edition of "Scheffer's Lectures" appeared (14). To this hook Bergman appended the first edition of his famous Table of Elective
In March 1773, Scheele sent Gahn a detailed report (lo!, and in November 1773 Bergman received a bulky manuscript intended for publication (9, 10) on Scheele's re-
Presented at the 168th Meeting of the American Chemical Society, Atlantic City, New Jersey, September 1974.
-
-.
-.
4) Clear demonstration that combustion occurs more vigorously in this gas than in atmospheric air.
5 ) Recognition that oxygen sustains respiration of animals better
than atmospheric air.
Furthermore, in order to determine who has priority for this discovery, three dates are of critical importance: (1) Date of the research and deductions upon which the discoverv is based. (2) Date of the first oral or w i t t e n communication of the discovery to competent scientific colleagues, and (3) Date of puhlication in a journal or hook. Concerning the Date of Original Research
By the evaluation of Manuscripts 52 (1772) and 53 (1771) it is shown that Scheele first obtained oxygen in about 1771 by heating MnOz with HzS04 18, 9 ! At first be believed that he had isolated ordinary air in which "fire burned brightly." Immediately after this, however, he named it "vitriol air" and distinguished it from ordinary air by quantitative combustion experiments. With research further performed by him up until about September 1771, Scheele fulfilled all five of our steps for the discovery of oxygen. Some historians of science, especially Nordenskiold (10) and Boklund ( I l l , have suggested that Scheele had first discovered oxygen as early as 1767-1768 by heating saltpeter. Nordenskiold confused the oxides of nitrogen (NO and NOz) with oxygen, and the conclusions drawn by Boklund have been disproven by recent research (.5, fif. Scheele f i s t prepared oxygen from saltpeter in about October 1772.
442 / Journal of Chemical Education
Attractions, which later appeared in two other editions, the second in Nova Acta Upsala (1.7a!, the third in his collected works (15! The Table in "Scheffer's Lectures" contained 45 columns, that in Noua Acta 50, and that in his collected works 59. Obviously Bergman was improving and adding new columns to his Table with each new edition. This hook too seems to have lain on the press for a considerable length of time with Bergman making additions during the time it was being composed. From Bergman's letter to Gahn of August 21, 1775 (9.)we can deduce that the last column, No. 45, manganese, could have been added to Bergman's Table in "Scheffer's Lectures" only after August 1775. Thus Bergman was still able to make additions to this book a t that time. Yet nowhere in this hook does Bergman refer to oxygen. Bergman therefore had come to know of Scheele's discovery of oxygen a t the earliest by the end of 1775, and more probably in January or February 1776 when he was looking over Scheele's manuscript for his book "Air and Fire" that he borrowed from the publisher Swederus in order to write a Foreword for the hook. Scheele wrote to Gahn (March 8, 1776) lamenting the delay in publication of his book: "I hear that Herr Professor Bergman has my manuscript with him. I will hope that he is not the cause of the delay" (lo!. On April 29, 1776, Bergman wrote to Scheele (in Koping): "I have read the first pages of your discussion of fire, and hope to get the proofs soon." In summary then, Bergman and Gahn first learned directly and unmistakably about Scheele's discovery of oxygen in late 1775 or earlv 1776. Lavoisier learned directlv From Scheele of his discbvery in September 1774 but in manner which could have led to Lavoisier's repeating the discovery thinking he was the original discoverer, since Scheele did not seem to know what he was doing. Furthermore, as Thomas Kuhn (Ifi! has said, if Scheele and Priestley had not discouered oxygen, Lavoisier would have had to invent it.
a
Concerning Date of Publication Until 1962 ( 1 ) i t was generally believed that Scheele had published the first disclosure of his discovery of oxygen in his hook "Air and Fire" of August 1777. But we now know (1-4) that Bergman's summary of Scheele's discovery, published in Nova Acta Upsala for 1775 (I%! was the first ~ublicationof Scheele's discoverv. But the date of publication of Vol. 2 of Noua Acta is-uncertain. The title Dace clearlv gives 1775 as the date of the publication. Let i s examine-some internal evidence which-proves that Vol. 2 of Noua Acta was not actually published until April 1776 a t the earliest. To his Table of Attractions in "Scheffer's Lectures" of 1774/1775 Bergman added five additional columns when he presented the same Table in Noua Acta (13a.!. In one of these added columns, Column 13, acidi acetosellae, he states f4,! that acidum acetosellae (oxalic acid) is not isolated from sal acetosellae in the same way a s tartaric acid is isolated from its calcium salt. "Mr. Scheele discovered another method," in which terra ponderosa (BaO) is used instead of calx (CaO) "but this recentlv discovered substance has been little' investigated so far" (4!. This statement corresponds closely with the contents of a letter from Scheele to Bergman of March 27, 1776. This seems to establish with certainty that Bergman made the last additions to his "Attractions" article in Noua Act0 (13a! in April 1776 and not before this date (7:. On the other hand, Scheele discussed the Table of Attractions from "Scheffer's Lectures" in a letter to Bergman dated May 26, 1776 (7). Scheele pointed out that it was not the metal itself hut its calx that dissolved in acids. Since Bergman made no such modification in his Table in Nova Acta (13a:. hut did later (1.5:. we can surmise that Bergman could no longer make changes in his Noua Acta article after Mav 1776.
Bergman made no allusions to Priestley's discovery of oxygen in his Nova Acta article (13a! whereas he quoted Priestley's work in his Opuscula version of the same article (15) in 1783. Bergman wrote Scheele in August 1776 (10) describing Priestley's research on oxygen which Bergman had learned from Swederus, iust returned from England. Thus August 1776 can he taken with confidence as the "terminus ante quem" for the final form of Bergman's Noua Acta article (13a! One strong argument against the last minute addition of Scheele's discovery to Bergman's Noua Acta article, however, is the existence of an illustration (see the figure). This illustration was included in Table VI, appended to Vol. 2 of Nova Acta, which included illustrations for other articles in Vol. 2. Bergman referred to the apparatus (the figure) as being used in his repetition of Scheele's preparation of oxygen. Seemingly such figures as this had to have been ordered a long time before final publication, and this fact would argue against any such last minute insertion a s that suggested here. But examination of Vol. 2 shows another article by Bergman, immediately preceding his "Attractions" article in Vol. 2, his article on "acid of air" (COz) (136). In this article Bergman uses the same apparatus (the figure) for his preparation of COz. Furthermore in referring to the apparatus in this "Attractions" article (13a! he uses only the letters G, H, and I, whereas in the "acid of air" article (136; he uses all the letters in the figure. Evidently Bergman used the figure in his "Attractions" article only to illustrate the pneumatic trough a s the apparatus used to collect the oxygen. The rest of the apparatus is clearly unsuitable for use in the experiment described in (13a! since vessel CD clearly contains a liquid, rather than a solid such as HgO would be. Vessel CD is clearly designed for a process such as that in Ref. (13b 1 wherein powdered limestone is added to acid to produce COz. With this knowledge we can now interpret what Bergman meant in his Nova Acta article ( 1 3 ~ :when he described the preparation of oxygen: "Following him (Scheele), I have conducted the following experiments, uarvinr the method but little" (4). The "little variation" wa> to .ub.tirute Bergman's pneumatir trough for Srheele's pig Madders fw collecting r he oxygen Conclusions 1) Scheele first observed oxygen and clearly understood what he was observing in June 1771, when he heated MnOz with concentrated H2S04.This was more than three years before Priestley or Lavoisier made similar observations. 2) Lavoisier received Scheele's letter and Priestley's oral communication at about the same time, in October 1774. But neither communication can be called a direct communication of the discovery of oxygen. Priestley in October 1774 confessed that he had no clear comprehension of oxygen. But in March 1775, friends of both Priestley and Lavoisier were informed of the discovery of oxygen in the sense of our five-point definition. Scheele in November 1775 first clearly informed his friend Gahn about his discovery, and Bergman at the beginning of 1716. 3) Lavoisier's discovery of oxygen was published in Rozier's Journal for May 1775. Priestley first published the details of his discoverv of oxveen in Vol. 2 of his "Exoeriments and Observa-
It would seem that Scheele has clear priority for the actual discovery of oxygen. As for communication of the discovery to others, the conclusions ere not clear, hut Scheele and Priestley seem to have nearly equal priority. With regard to date of publication by one of the original discoverers, Priestley seems to have priority over Scheele. But if we consider publication by other than the original discoverers, Lavoisier actually may have priority here. And some historians may even want to argue that Lavoisier could have been an original discoverer, himself. And we hope Partington will not turn over in his grave. Volume 52, Number 7. July 1975 / 443
Literature Cited
(10) ~ ~ ~ d ~A. ~N,~ -earl k i wilhaim ~ ~ d~ . e h d P~ ~' ~s ~ htters ~ u ~and~ N O w~ ~ S . ' ' Stockholm. 1892. ( I l l Boklund, U., "Carl Wilholm Schoole," Bruna Boken. Stackholm. 1961. 1121 Scheele. C. W.. "Somliiche Phyaicho und Chernlsrhs Wwke," (German franrlafion by Hermbrradr, S. F.1. Berlin. 1793. (131 Bergman, T., Now A d o Re&< Scienliorum U p d i e n m . Vol. II. J o h Edman. Upaala. 1775, (a1 "Di$quirilio de Attract ianibus Elnciiuir" pp. 159-248, (Engliih trandalioninld!.) ibl "CommenfaliodeActdnA~ro."pp.I C B - 1 3 . (141 Bergman. T.. "Chsrnish Forddsningor . . . H. T. Schelfer," Upsala. 1715. Later publilhed i n s German translation as "Chemirche Voriesuwan . . . H T. Schef~ (er," (Edrlor: Bergman, T.I. Greifswald, 1779. (161 Bereman. T., "Opusculo Physim ef Chernieo." Vol I, Holmae, 1719; Vol. 11, Upsala, 17RO;Vol.IIl. Lipaiso. 1783. (161 ~ u h " . ~ h o m a r ,'structure of scientific ~evolutionr." Univ of Chicago Press, 1961.
Parfinam. J.R.. J.CHEM. U)UC., D. 123 119621. Partington. J. R.."HistoryoiChemistrv." Vol. 3. London. 1962. SchuOe..I.A.. Bull. New Mexico Acad. o f L i . . 17.l2).9-10(L9661. SchuOe. J. A.. "Bergman's Disrertation on Elective Attmctionr." English tranal. of 11Jo). Johnson Reprint Corporation. NewYork, 1968. (51 Casrebaum. H.. Die Phormazc~.28.479 (19731. (61 Carsebaum. H.. NTM-Schriflenr-(ierch. Noluruirr.. Teehnik M s d . Leipnig, ,974. (in pres~l. I71 Carrebaum. H.. DiePhorrnolie. 29I91.6W-60r 119741. (8) Oaeen. C. W., "Carl Wilhslrn Schade, Hondschrilfan 1756-1777," (Editor Oneen. C. W.I. Upsala. 1942. 191 Osoon. C. w.. Kunpi. Sum& Vetenah. ~cdomoier, I. ~ o f t eI. pp. 27-59 (1919-L943). Ill ('21 I31 I41
.
+
444 / Journal of ChernicalEducdtbn
