Dr. Kolbe on the Formation of Nitric Acid, fyc. 543 



exists between the particles of the metal which conducts the 

 current : it is as follows : — 



" If we make the current of the battery of sixty elements 

 pass through a platina, iron, copper, or any metallic wire, the 

 metal at first reddens, then it melts, and after some instants this 

 fused metallic wire, in which various movements are perceived, 

 breaks at an undetermined place, and the ends formed by the 

 rupture are projected far along the wire; this wire is, after 

 the experiment, terminated, at the spot where it has been 

 broken by the force of the current, by two globules. This 

 phenomenon is not accompanied by any evolution of light or 

 any combustion. The wire neither gains nor loses in weight 

 in this experiment ; there is only the ordinary spark which 

 appears at the moment when the repulsion produces its effect, 

 and when the wire is divided into two fragments." 

 Teylerian Museum, Haarlem, 

 August 20, 1846. 



Note. On the subject of this Paper see Mr. Grove's Lecture on the 

 Voltaic Arc at the Royal Institution in February 1845, in the Literary 

 Gazette.— Ed. 



LXXIV. On the Formation of Nitric Acid in Eudiometric 



Combustions of Gases mixed with Nitrogen. By Dr. H. 



Kolbe*. 

 T N an analysis of mixed gases, which contained 90 parts of 

 -*- light carburetted hydrogen and 10 parts of nitrogen, I 

 have often found, that by the combustion in the eudiometer 

 more oxygen disappeared than in accordance with the calcu- 

 lation ought to have disappeared. The explosion caused 

 always such an elevation of temperature, that the mercury 

 sublimed and covered the inside of the eudiometer with a thin, 

 gray, metallic film. After the caustic potash-ball was intro- 

 duced into the eudiometer for the purpose of absorbing the 

 carbonic acid formed, and the residual volume of gas dried, 

 the diaphanous film of mercury was seen to be covered by 

 innumerable little white crystals, the behaviour of which with 

 water, muriatic acid and caustic potash, showed clearly that 

 they contained protoxide of mercury for their basis. 



If these crystals consist of nitrate of protoxide of mercury, 

 as the well-known experiments by Cavendish on the forma- 

 tion of nitric acid render probable, then the before-mentioned 

 diminution of the volume is easily understood. 



Therefore, trying at first whether this error was occasioned 

 only by the presence of nitrogen, I mixed a certain volume 

 of pure hydrogen with an excess of oxygen in an eudiometerf 



* Communicated by the Chemical Society; having been read May 18, 

 1846. 

 •f In all these experiments I used an eudiometer which was furnished 



