ON tllE NEW kEtALS. 365 



to the foundations of a discoTery, if not to the discotcry t'rench admit 



•^ , Mr. Davy's 



itself, than our neighbours on the contiuent, yet on this claim to the 

 occasion they have been anticipated at home : for.in a report '^'^'^'^^^fy- 

 of the Polytechnic School, published in the last Number of 

 the Phil. Magazine, it is said by the editors of the journal 

 of the Polytechnic School, " that Mr. Gay Lussac, and 

 Mr. Thenard, had repeated Mr. Davy's experiments, and 

 obtained the two new metals, of which the existence had 

 not been suspected previous to Mr. Davy's experiments." 



You say, it is no derogation to Mr. Davy's merits, that Mr. Davy's 

 he has explored the processes of nature by simplicity of in- ^^^^^^Tt 

 vestigation, and clear deductions grounded upon a know- 

 ledge of the antecedent analogies. On the last part of this 

 proposition I cannot agree with you. It would in my 

 opinion have been a derogation to his merit, had he been 

 guided by any analogies so loose as those, which might have 

 led him to look for metals in the fixed alkalis. He was ou 

 the contrary enlightened by new principles of research, 

 arising from the knowledge of the properties of chemical 

 decomposition by Voltaic electricity, which your useful 

 labours partly led the way to, and which his discoveries 

 ibave made almost universal. 



I attended his course of lectures of 1807, and in referring The negative 

 to my notes I find, that he stated it as a fact, that all bodies o^iy infl'^^mvia^ 

 •of known composition attracted by the negative pole in the ble matter. 

 Voltaic circuit consisted principally of inilaniroable matter^ 

 and were naturally positive; and that it was probable there- 

 fore, that all bodies of unknown composition attracfed by 

 this pole, and which were naturally positive, miglit also 

 contain inflammable matter. 



In his lectures in 1801, he stated, that, in looking forfl"^he inokoi- 

 inflammable matter after those ideas in the fixed alkalis, 

 he had t/wcoyererf it, and that he had likewise found what 

 he had not expected, that it was metallic in its nature. 



In this instance sagacious conjecture and sound analogy 

 were followed up by experimental research, and ended in 

 a great discovery. 



Guesses, except from experimental inquirers, ought Guesses \r\ 

 scarcely to be tolerated in science; and to attacli import- 

 ance to them, and to dignify them with approbation, is 



merely 



