276 M. Arago's Biographical Memoir of James TF'att. 



reserve, and which Priestley, regardless of the fresh honour it 

 brought him, set himself deliberately to overturn, — deserves to 

 be recorded in the history of science as a great discovery, what- 

 ever notion our present intimacy with the subject might lead 

 us to adopt concerning it.* 



Bleacliing hy means of Chlorine^ the beautiful invention of 

 Berthollet, was introduced into Britain by James Watt, soon 

 after having paid a visit to Paris, towards the end of the year 

 1786. t He constructed all the necessary apparatus, directed 

 their suitable arrangement, superintended the first trials, and 

 then confided to his father-in-law Mr Macgregor, the general 

 introduction of the valuable improvement. In spite of all the 

 urgent solicitations of the illustrious engineer, our celebrated 

 countryman obstinately refused (however extraordinary it may 

 appear in the age in which we live) to be associated in an 

 undertaking which, to him, was free from risk, and of which, 

 it appeared, the profits must be very gi'eat. 



No sooner, in the latter half of the last century, were the 

 numerous gases discovered, and the important agency they 

 exerted in the explanation of chemical phenomena, than the 

 question of their employment as powerful medicines was can- 

 vassed and advocated. Dr Beddoes especially prosecuted this 

 subject with sagacity and perseverance. With the help of 

 private subscriptions, he was enabled to establish at Clifton, 



•■* Lord Brougham was present at the public meeting of the Institute, 

 when, in the name of the Academy of Sciences, I paid this tribute of gi-ati- 

 tude and admiration to the memory of Watt. On his return to England, 

 he collected some valuable documents, and studied anew the historical 

 question to which I have devoted so much space in this memoir. He in- 

 vestigated the subject, in his usual masterly style, and with that scrupu- 

 lous care, in some degree judicial, which might be expected from the for- 

 mer Lord Chancellor of Great Britain. I owe it to an act of kindness 

 which I duly appreciate, that I am able to present to the iniblic the result 

 of the labours of mj' illustrious fellow member. (See page 316 of tlie pre- 

 sent No.) 



t This journey was undertaken -with Mr Boulton, at the instance of the 

 French Ministry, to advise them respecting the substitution of steam for 

 water, as the moving power in the water-works at Marly. The state of 

 the finances, and the approaching revolution, put an end to the plan at Ihc 

 time. — Edit. 



