20 Mr. Miller on the Oxidation of Palladium* [July, 



substances, is evident from the production of the acetic acid 

 vapours and the blue flame. 



Platinum stands to copper (in relation to its power of conduct- 

 ing heat) almost as 1 to 9. 



As many experiments with platinum wire do not succeed 

 unless the wire be sufficiently thick so that the heat may be 

 retained, and a larger surface afforded for action, yet the success 

 of the above experiments is not materially influenced by attend- 

 ing to this circumstance, the conducting power of copper, iron, 

 &c. beinor increased with the bulk and surface of the metal. 



One cncumstance it may be worthy to notice, viz. that the 

 ether or alcohol used in repeating the above experiments should 

 be very pure, and frequently changed, a fresh portion being 

 allotted for the trial of each, and the evaporating dish in which 

 it is poured should have a moderate capacity ; if it be too wide, 

 the vapour of ether is not in sufficient quantity to produce the 

 desired effect ; or if very contracted, the atmosphere round the 

 wire will solely consist of ether ; the air not gaining admission, 

 this may be remedied by raising the heated wire to that point 

 where the two (the air and stratum of alcoholic or ethereal 

 vapour) may be said to mingle. 



Article IV. 



On the Oxidation of Palladium during its effecting the Union of 

 the Hydrogen and Oxygen Gases from Ether, Alcohol, S^c. By 

 H. B. Miller, Esq. 



(To the Editors of the Annals of Philosophy.) 



GENTLEMEN, Bnstol, MayW, 1826. 



In a paper which I had the honour to read at a meeting of 

 the Literary and Philosophical Society annexed to the Bristol 

 Institution, on the 26th of August, 1824, the Very Reverend the 

 Dean of Bristol in the Chair, I stated an anomalous fact which 

 had occurred in experimenting on a slip of palladium. Its infe- 

 rior surface, after it had become incandescent either over the 

 ether, alcohol, essential oils, or gaseous mixtures (a property 

 which this metal possesses in common with platinum) became 

 covered with a black substance. By uniting the shp of palla- 

 dium with various metals, no alteration ensued, neither by insu- 

 lation, so that electricity had no influence on this phenomenon. 

 Many circumstances then induced me to consider it as carbon 

 deposited from the various fluids and gases experimented on ; 

 but why it should rather adhere to the palladium than the 

 platinum, I was then unable to ascertain, unless it was attribu- 

 table to the former metal effecting the combination of the oxygen 



