September 4, 1890] 



NATURE 



451 



and of several other substances with nitric acid, has been named 



by him dephlogisticatedair." 



In the " Traite Elementaire de Chimie" the claim for partici- 

 pation is again asserted in these words : "This air, which Mr. 

 Priestley, Mr. Scheele, and I discovered at about the same 

 time ..." 



Now, there is no question that Lavoisier knew of the existence 

 of oxygen some months before he made the experiments with 

 the burning-glass of M. Trudaine at Montigny, for the simple 

 reason thai Priestley had already told him of it. Priestley left 

 Leeds in 1773 to become the librarian and literary companion 

 of Lord Shelburne, and in the autumn of 1774 he accompanied 

 his lordship on to the Continent, and spent the month of 

 October in Paris. Lavoisier was famous for his hospitality ; his 

 dinners were celebrated ; and Priestley, in common with every 

 foreign savant of note who visited Paris at that period, was a 

 welcome guest. What followed is best told in Priestley's own 

 words :—" Having made the discovery [of oxygen] some time 

 before I was in Paris, in the year 1774, I mentioned it at the 

 table of Mr. Lavoisier, when most of the philosophical people 

 of the city were present, saying that it was a kind of air in 

 which a candle burnt much better than in common air, but I 

 had not then given it any name. At this all the company, and 

 Mr. and Mrs. Lavoisier as much as any, expressed great sur- 

 prise. I told them I had gotten it from precipitate per se and 

 also from red lead. Speaking French very imperfectly, and 

 being little acquainted with the terms of chemistry, I said plombe 

 7 ouge, which was not understood till Mr. Macquer said I must 

 mean minium." 



In his account of his own work on dephlogisticated air, given 

 in his " Observations," &c., 1790 edition, he further says, vol. 

 ii. p. 108 : " Being at Paris in the October following [the August 

 of ^774]._ and knowing that there were several very eminent 

 chemists in that place, I did not omit the opportunity, by means 

 of my friend Mr. Magellan,^ to get an ounce oi mercurius calci- 

 natus prepared by Mr. Cadet, of the genuineness of which 

 there could not possibly be any suspicion ; and, at the same 

 time, I frequently mentioned my surprise at the kind of air 

 which I had got from this preparation to Mr. Lavoisier, Mr. le 

 Roy, and several other philosophers, who honoured me with 

 their notice in that city, and who, I dare say, cannot fail to 

 recollect the circumstance." 



If any further evidence is required to prove that Lavoisier was 

 not only not "the true and first discoverer " of oxygen, but 

 that he has absolutely no claim to be regarded even as a later 

 and independent discoverer, it is supplied by M. Berthelot him- 

 self. Not the least valuable portion of M. Berthelot's book, as 

 an historical work, is that which .he devotes to the analysis of 

 the thirteen laboratory journals of Lavoisier, which have been 

 deposited, by the pious care of M. de Chazelles, his heir, in the 

 archives of the Institute. M. Berthelot has given us a synopsis 

 of the contents of almost every page of these journals, with 

 explanatory remarks and dates when these could be ascertained. 

 As he well says, these journals "are of great interest because 

 they inform us of Lavoisier's methods of work and of the direc- 

 tion of his mind — I mean the successive steps in the evolution of 

 his private thought." On the fly-leaf of the third journal is 

 written " dti 23 Mars, 1774, au 13/A'nVr, 1776." From p. 30 

 we glean that Lavoisier visited his friend M. Trudaine at 

 Montigny about ten days after his conversation with Priestley, 

 and repeated the latter's experiments on the marine acid and 

 alkaline airs (hydrochloric acid gas and ammonia). He is again 

 at Montigny some time between February 28 and March 31, 

 1775, and repeats not only Priestley's experiments on the 

 • iecomposition of mercuric oxide, presumably by means of M. 

 Tiudaine's famous burning-glass, but also his observations on the 

 character of the gas. The fly-leaf of the fourth journal informs 

 us that it extends from February 13, 1776, to March 3, 1778. 

 < )n p. I is an account of experiments made February 13 on 

 ■ precipite per se de chez M. Baume," in which the disengaged 

 is is spoken of as."l'air dcphlogistique de M. Prisley" {sic). 

 iich a phrase in a private notebook is absolutely inconsistent 

 -vith the idea that at this time Lavoisier considered himself as 

 an independent discoverer of the gas. How he came to regard 

 himself as such we need not inquire. Nor is it necessary to 

 occupy your time by any examination of the arguments by which 



\ Prof. Orimaux (" Lavoisier," p. 51), says: "Undeses[Lavoiiier's]amis 

 !ui habitait Londres, Magalhaens ou Magellan, de la famille du celebre 

 •. . igateur, lui envoyait tous les memoires sur les sciences qui paraissaient en 

 i,'leterre, et le tenait au courant des decouvertes de Priestley." 



NO. 1088, VOL. 42] 



M. Berthelot, with the skill of a practised advocate, would seem 

 to identify himself with the case of his client. We would do 

 him the justice of recognizing the difficulty of his position. He 

 seeks to discharge an obligation of which the acknowledgment 

 has been too long. delayed. The Academie des Sciences a year 

 ago awoke to the sense of its debt of gratitude to the memory 

 of the man who had laboured so zealously for its honour, and 

 even for its existence, during the stormy period of which France 

 has just celebrated the centenary, and out of the etoge on La- 

 voisier which M. Berthelot, as Perpetual Secretary, was com- 

 missioned to deliver, has grown " La Revolution Chimique." To 

 write eulogy, however, is not necessarily to write history. We 

 cannot but think that M. Berthelot has been hampered by his 

 position, and that his opinion, or at least the free expression of it, 

 has been fettered by the conditions under which he has written. 

 We imagine we discern between the lines the consciousness that, 

 to use Brougham's phrase, the brightness of the illustrious career 

 which he eulogizes is dimmed with spots which a regard for 

 historical truth will not permit him wholly to ignore. 



Two cardinal facts made the downfall of phlogiston complete 

 —the discovery of oxygen, and the determination of the com- 

 pound nature of water. M. Berthelot's contention is that not 

 oily did Lavoisier effect the overthrow, but he also discovered 

 the facts. In other words, he has not only a claim to a partici- 

 pation in the discovery of oxygen, but he is also " the true and 

 first discoverer " of the non-elementary nature of water. This 

 second claim is directly and explicitly stated. Although it is 

 supported by a certain ingenuity of argument, we venture to 

 think that we shall be able to show it has no greater foundation 

 in reality than the first. 



Members of the British Association, who are at all familiar 

 with its history, will recall the fact that this is not the first 

 occasion on which the attempt to transfer " those laurels which 

 both time and truth have fixed upon the brow of Cavendish" 

 has had to be resisted. At the Birmingham meeting of 1839 the 

 Rev. W. Vernon Harcourt, who then presided, devoted a large 

 portion of his address to an able and eloquent vindication of 

 Cavendish's rights. The attack came then as now from the 

 Perpetual Secretary of the French Academy, and the charges 

 were also formulated then, as now, in an eloge read before that 

 learned body. The assailant was M. Arago, who did battle, 

 not for his countryman, Lavoisier, whose claims are dismissed as 

 " pretensions," but on behalf of James Watt, the great engineer, 

 who was one of the foreign members of the Institute. 



It is not my wish to trouble you at any length with the details 

 of what has come to be known in the history of scientific dis- 

 covery as the Water Controversy — a controversy which has 

 exercised the minds and pens of Harcourt, Whewell, Peacock, 

 and Brougham in England ; of Brewster, Jeffrey, Muirhead, 

 and Wilson in Scotland ; of Kopp in Germany ; and of Ara^jo 

 and Dumas in France. This controversy, it has been said, takes 

 its place in the history of science side by side with the discussion 

 between Newton and Leibnitz concerning the invention of the 

 Differential Calculus, and that between the friends of Adams 

 and Leverrier in reference to the discovery of the planet Neptune. 

 Up to now it has practically turned upon the relative merits of 

 Cavendish and Watt. M. Berthelot is the first French savant of 

 any note who has seriously put forward the claims of Lavoisier, 

 his countryman and predecessor Dumas having deliberately re- 

 jected them. 



At the risk of wearying you with detail, I am under the 

 necessity of restating the facts in order to make the position 

 clear. Some time before April 18, 1781, Priestley made what he 

 called "a random experiment " for the entertainment of a few 

 philosophical friends. It consisted in exploding a mixture 01 

 inflammable air (presumably hydrogen) and common air, con- 

 tained in a closed glass vessel, by the electric spark, in the 

 manner first practised by Volta in 1776. The experiment was 

 witnessed by Mr. John Warltire, a lecturer on natural philosophy 

 and a friend of Priestley, who had rendered him the signal service 

 of giving him the sample of the mercuric oxide from which he ha J 

 first obtained oxygen. Warltire drew Priestley's attention to the 

 fact that after the explosion the sides of the glass vessel were 

 bedewed with moisture. Neither of the experimenters attached 

 any importance to the circumstance at the time, Priestley being 

 of opinion that the moisture was pre-existent in the gases, as no 

 special pains were taken to dry them. Warltire, however, con- 

 ceived the notion that the experiment would afford the means of 

 determining whether heat was ponderable or not, and hence he 

 was led to repeat it, firing the mixture in a copper vessel for 



