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THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[November, 



liright fit of genius, disapjiear eutirely from the liistory of science. Such was 

 Mai-liirc, of whom tlie chronological order of dates leads me to relate a ti'uly 

 reraarkalile exiieriment. In the heginning of the vear 1 781, this iihilosoplie'r 

 conceived that an electric spark could not traverse certain gaseous combina- 

 tions \vitliout subjecting them to certain changes. An idea so novel, nns\i"-- 

 gestcd by any existing analogy, and of which so many important applications 

 have since been made, would I should have thought have earned for its author, 

 that aU men of science should not forget to attrilnite to him the honour of 

 It. W arltire was deceived with regard to the precise natiu-e of the changes 

 winch electricity might engender; fortunatelv for him he foresaw that they 

 would be accompanied with an explosion, and for this reason he first made 

 the experiment in a metal vessel, in which he inclosed air and hydrogen. 

 Cavendish soon after repeated the expciiment of Warltire. The cer/ain date 

 of his lal)om-s (I designate in this manner any date resulting from an authentic 

 document, oran academical or a printed ii'aper) is anterior to the mouth of 

 April 1 783, since Priestley quotes Cavendish's experiments in a paper on t!ie 

 21st of the same month. The cpiotation moreover informs lis only of one 

 thing, that Cavendish had obtained water by the detonation of a mixture of 

 oxygen and hydrogen, a fact already demonstrated by Waritirc, In his paper 

 of the month of April, Priestley added an important cu'cumstance to tliose 

 which resulted from the experiments of his predecessors. He proved that the 

 weight of the water which is deposited on the surfaces of the vessel at the 

 moment of the detonation of the oxygen and the hvdi'ogen is the sura- of the 

 weight of the two gases. 



Watt, to whom Priestley communicated this important result, saw imme- 

 diately in it with the penetration of a superior man, a proof that water was 

 not a simple body. " What are the products of your experiment ?" wTote he 

 to his illustrious frienil, " water, lujkt and heat, kxe^ we not from that war- 

 ranted in concluding that water is composed of two gases, oxygen and hydro- 

 gen, deprived of a portion of their latent or elementary heat, and that oxygen 

 IS water deprived of its hydrogen, but united to latent" heat or light. If light 

 he only a modification of heat, or a mere circumstance of its manifestation, 

 or a component part of hydrogen, oxygen gas must be water deprived of its 

 hydrogen hut united to latent heat." 



This clear, plain and methodic passage is extracted from a letter of 

 A\ att s of the 2Gth April, 1 783. The letter was communicated bv Priestley to 

 several savants in London, and afterwards delivered to Sir Josei.h Banks, 

 President of the Royal Society, to l,e read at one of the meetings of that 

 learned body. Circumstances wliich I suppress because thcv are of no im- 

 portance m the present discussion, caused the reading of this letter to he 

 deferred for a year, but the letter was preserj'ed in the records of the society, 

 and IS pulihshed in the 7-lth volume of the Philosophical Transactions, with 

 Its true date of the 26th of April, 1 783. It was embodied by the SccretaiT of 

 tlie Royal Society himsetf, at the time of going to press, with a letter from 

 Matt to De Luc, dated the 26th November, 1783. 



, I do not ask any indulgence for this profusion of details ; it must be oh- 

 served tliat a minute comparison of dates can alone show tlie truth fully, and 

 that it is a question of one of those discoveries which confer the most honour 

 on the human mind. Among the claimants to this prolific discovery, we shall 

 find two of tlie greatest chemists of which France and England can boast— 

 every one will name Lavoisier and Cavendish. The date of the public read- 

 ing of the paper in which Lavoisier gave an account of his experiments, and 

 in which he developed his views on the production of water by the combus- 

 tion of oxygen and hytkogen is two months later than the date of the de- 

 position of the ah-eady analyzed letter of Watt in the records of the Roval 

 Society of London. The celeljrated paper of Cavendish, entitled E.rperimmts 

 upon Air, is later still, it was read on the 1.5th Januai-y, 1784. We ought cer- 

 tainly to feel surprised that facts so well authenticated, could become the 

 subject of a sharp controversy, hut I must call your attention to a circum- 

 stance to which I have not yet alluded. Lavoisier declared in positive terms 

 that Blagden, the Secretary of the Royal Society of London, was present at 

 his first expenments on the 24th of June, 1783, and that " he informed him 

 that Cavendish had already tried in London to burn hydrogen gas in closed 

 vessels, but without having obtained any veiT considerable quantity of water." 

 Cavendish also relates in his paper the communication made to Lavoisier by 

 Blagdon, and according to him it was much more extensive than the French 

 chemist acknowledged. He said that the communication related to the con- 

 clusions to which his experiments lead, namely, the theory of the composition 

 of water. Blagden made a party liimself in' the dispute, wrote in Crell's 

 Journal, in 1786, confirming Cavendish's assertion. According to him the 

 experiments of the academician of Paris were only a mere verification of 

 those of tlie English chemist. He maintained that he had informed Lavoisier 

 that the water produced at London had a weight precisely equal to the sum 

 of the weight of the two gases consumed. Lavoisier, adds Blagden in con- 

 clusion, has told the truth, hut not the whole truth. 



Such a reproach is severe— were it true, should I not much diminish the 

 weight of it, if I show that. Watt excepted, all those whose names figure in 

 this history, are more or less exposed to it. Priestley relates in detail, and 

 as Ins, expenments fi-om which it ajipears that the water engendered by the 

 detonation of a mi.xture of oxygen and hydrogen has a weight exactly equal 

 to that ot the two gases consumed. Cavendish some time afterwards claimed 

 this result as his own, .and insinuated th.it he had communicated it verbally 

 to the Birmingham chemist. 



Cavendish deduces as a consequence from tliis etpiality of weight that 

 water is not a simple body. In the first place he makes no mention of the 



paper jdaced in the arcluves of llie Royal Society, in which Watt developed 

 the same idea. It is true that when it came to be printed, AVatt's name is 

 not forgotten ; but it wiis not among the records that the idea of the cele- 

 brated engineer was seen; but he declares that he knew of it, by its having 

 been read lately at one of the meetings. Now, however, it has been clearly 

 proved, that it was not read till some months after that in which Cavendish 

 speaks of it. 



On entering upon this important discussion Blagden announces his in- 

 tention to clear up every thing, and to put it upon a firm basis. He does 

 not flee in fact, from any accusation, from the citation of any date, so long as 

 it is a question of securing to his friend and protector Cavendish, the priority 

 over the French chemists ; as soon however as it relates to his two fellow- 

 countrymen, his explanations become vague and uncertain. " In the spring 

 of 1783," said he, " Mr. Cavendish showed us that he drew as a consequence 

 from his experiments, that oxygen is notliing more than water deprived of its 

 idilogiston, (that is to say, deprived of its hydrogen). At/out the same time, 

 news arrivecl in London, that Mr. M'att of Birmingham had been led by some 

 observ.ations to a similar opinion." This expression, about the same time, to 

 speak in Blagden's way, cannot be the whole truth. About the same time, 

 settles nothing ; questions of priority may depend on weeks, days, hours and 

 minutes. To be clear and precise as he had promised, he should have said 

 whether the verbal communication made by Cavendish to several members of 

 the Royiil Society, preceded or followed the arriv.al in London of the news 

 respecting the labours of Watt. Can it lie supposed that Blagden would not 

 have explained a fact of this importance, if he could have quoted an authentic 

 date in favour of his friend ? 



To render the imbrorjUo complete, the compositors and printers of the 

 Philowpliical Transactions also took a hand in it. Several dates are incor- 

 rectly related, and in a separate copy of his paper ihstrilnited by Cavendish 

 to several scientific men, 1 perceive an eiTor of a whole ve.ir. By an unfor- 

 tunate fatality, for it is a real misfortune to give way involuntarily to vinfor- 

 tunate and unmerited susiiicions none of these printed errors are favourable 

 to \Vatt. God forbid that I should endeavour to inculpate by these remarks 

 the literary probity of the illustrious savants whose names I have quoted. 

 They only prove that in matters of lUscovery, the strictest justice is all that 

 can be expected from a rival or a competitor, however eminent his reputa- 

 tion may already be. Cavendish hardly hstened to his steward when he 

 consulted him about the investment of his millions ; you can tell now whether 

 he was equally indifferent as to his experiments. We shall not he therefore 

 too fastidious in requiring in imitation of judges of civil causes, that the his- 

 torians of science should only collect written documents as available proofs ; 

 perhaps too 1 ought to add, published docnments. Then, but only then, would 

 a stop be put to those disputes perpetually breaking out .it the expense of 

 national vanity ; and thus the name of Watt would resume in the history of 

 chemistry the exalted position which belongs to him. The solution of a 

 question of priority when it is based, like this in which I have just been en- 

 gaged, upon an attentive examination of juinted pajiers, and on a minute 

 comparison of dates, assumes the character of a trae demonstration.* How- 

 ever 1 do not consider myself bound to dispense with running rapidly over 

 the various ilifficuUies to which well judging minds seem to me to have at- 

 tached some importance. 



How can we, say they, admit that in the midst of an immense wiiirhrind 

 of commercial affairs, that busily engaged witli a multitude of Lawsuits, that 

 obhgcd to ]iroyide every day by inventions for the (hfticulties of an infant 

 factory, Watt could have found time to follow step by step the progress of 

 chemistry, make new discoveries, and propose explanations of which masters 

 of the science would never have thought .'t 



I shall give a sliort but conclusive answer to this objection : I hare now in 

 my possession copies of an active correspondence, jirincipfilly relating to che- 

 mical subjects, wiiich Watt carried on during 1782, 3 ii 4, with Priestley, 

 Black, De Luc, Smeaton, Gilbert Hamilton of Glasgow, and Fiy of Bristol. 



Here, however, is an objection which seems to me more specious, as it is 

 jirompted by a deej) knowledge of the human heart. The discovery of the 

 composition of water proceeding at the same time as the admirable inventions 

 combined in the steam-engine, can it he supposed that Watt would have 

 consented with goodwill, or at least without testifying his displeasure, to see 

 himself stripped of the honour, which it ought eternally to confer upon his 

 name ? 



This reasoning fails in its very premises; Watt never renounced the share 

 wiiich legitimately accrued to him in the tliscovery of the composition of 

 water. lie scrupulously caused his paper to be published in the Philosophical 

 Transactions. A detailed note states authentically the date of presentation 

 of each paragraph of this document. What could a philosojihcr of M'att's 

 character do more, or what ouglit he to do, but await patiently the day of 

 ustico. Besides, it wanted but very little that an unfortunate blunder did 



• When Don Quixote attacked the sheep, he asked Sancho whether lie did not see the 

 haniK-rrt of tile opposint; armies fiying in the air, and llie trumpets calling to combat ; and 

 M. Ara^o, with equal contidence, talks of an attentive examination of printed papers, 

 and a minute comparison of dntes, wiih all the coolness of a German professor, who has 

 just smoked out a laborious mass of absurdity upon a question of Greek history, from the 

 accumulated dust of a thousand volumes. M. Arayo has a very small whistle to shew 

 for his money. — Note of the Translator, 



+ M. Arago, like Walter Scott in his History of Napoleon, havinc raised fictitious oh. 

 jections, linds no ditfieulty in answering Iheiii by a similar inaenions process; of tliie 

 nature are the men of straw now hefore us, wliicli it is niiKli more easy to demolish than 

 Uie more serious objections which have really been made. As 'I'om Thumb says, " be 

 made the giants first, and then he killed them.— .'Vyic of tli£ Translator. 



