322 EXPERIMENTAL INVESTIGATIONS. 



This experiment, although, coupled .with the previous ones, 

 tolerably conclusive, did not satisfy me, and I attacked the 

 difficulty in another manner. The experiment (fig. 5) in- 

 duced me to believe that if I could get platinum ignited 

 under water, so as to be in an atmosphere of steam, decompo- 

 sition would take place ; and M. Boutigny's experiments on 

 the spheroidal state of water led me to hope I might keep 

 platinum for some time under conditions suitable for my 

 purpose. 



After a few failures I succeeded perfectly by the following 

 experiment. The extremity of a stout platinum wire was 

 fused into a globule of the size of a peppercorn by a nitric acid 

 battery of 30 cells ; prepared water was kept simmering by a 

 spirit-lamp, with a tube filled with water inverted in it ; char- 

 coal being the negative terminal, the voltaic arc was taken 

 between that and the platinum globule until the latter was at 

 the point of fusion ; the circuit was now broken, and the highly 

 incandescent platinum plunged into the prepared water : sepa- 

 rate pearly bubbles of gas rose into the tube, presenting a 

 somewhat similar effect to Experiment (fig. 5). The process 

 was repeated, the globule being frequently plunged into the 

 water in a state of partial fusion ; and when a sufficient quan- 

 tity of gas was collected it was examined ; it detonated, leaving 

 0*4 residue ; this was as usual nitrogen with a trace of oxygen. 

 A second experiment gave a still better result, the gas con- 

 tracting to 0*25 of its original volume. 



On making the platinum negative and the charcoal posi- 

 tive a very different result followed; the carbon was, as is 

 known to electricians, projected upon the platinum ; and the 

 gas in this case was mixed with carburetted hydrogen and 

 carbonic oxide. I know no experiment which shows so 

 strikingly the different effects at the disruptive terminals as 

 this ; when the platinum is negative it gives much carbonic 

 gas, when it is positive, not a trace (the gas was delicately and 

 carefully tested for it) ; nay, more, by changing the platinum 

 from negative to positive the carbon is instantly removed, and 

 in a single experiment the platinum becomes perfectly clean. 



Here then I produced very satisfactorily decomposition by 

 heat ; it is true the battery was used, but used only as a means of 



