•16 Dr Davy's liemarks on the Claims to the 



reluctance to lay my thoughts on these subjects (the pro- 

 bable causes of the production of water from the deflagra- 

 tion of a mixture of dephlogisticated and inflammable air) 

 before the public, in their present indigested state, and with- 

 out being able to bring them to the test of such experiments, 

 as would confirm or refute them, and should therefore have 

 delayed the publication of them until these experiments had 

 been made, if you, Sir, and some other of my philosophical 

 friends, had not thought them as plausible as any other con- 

 jectures which have been fomiied on the subject; and that, 

 though they should not be verified by further experiments, 

 or approved by men of science in general, they may, perhaps, 

 merit discussion, and give rise to experiments which may 

 throw light on so important a subject," adding " I first 

 thought of this way of solving the phenomena, in endeavour- 

 ing to account for an experiment of Dr Priestley's, wherein 

 water appeared to be converted into air, and I communicated 

 my sentiments in a letter addressed to him, dated April 26, 

 1783, with a request that he would do me the honour to lay 

 them before the Royal Society ; but as before he had an op- 

 portunity of doing me that favour, he found, in the prosecu- 

 tion of his experiments, that the apparent conversion of wa- 

 ter into air, by exposing it to heat in porous earthen vessels, 

 was not a real transmutation, but an exchange of the elastic 

 fluid for the liquid, in some manner not yet accounted for ; 

 therefore, as my theory was no w-ays applicable to the explain- 

 ing these experiments, I thought proper to delay its publica- 

 tion, that I might examine the subject more deliberately, which 

 my other avocations have prevented me from doing to this 

 time." 



Mr Watt's paper in the Transactions of the Royal Society, 

 bearing the date of November 26, 1783, and which was read 

 the 29th April 1784, consisted, it must be remembered, of 

 portions of his original letter to Dr Priestley, and of ad- 

 ditions, some of w^hich, it may be inferred, were made shortly 

 before it was read, viz.-, in the " corrected copy,"* and when 



* It is designated, in Mr Watt's handwriting, " Corrected copy of a letter 

 from James Watt, Engineer, to M. de Luc, dated November 26, 1783, corrected 

 April 17S-1." It is in the Archives of the Royal Society. 



