DECOMPOSITION OF WATER BY HEAT. 323 



fusing the platinum, as this was, as soon as fused, entirely 

 separated from the circuit and could have no possible voltaic 

 action. Wishing, however, altogether to avoid the use of the 

 battery, I repeated this experiment, employing as my means 

 of fusing the platinum the oxyhydrogen blowpipe ; the ex- 

 periment was equally successful, indeed rather more so, as 

 the manipulation was more easy. 



I could readily by this means collect half a cubic inch or 

 more of the 'gas ; when detonated, the residue of nitrogen 

 averaged 0*35 of the original volume. 



In carefully watching this experiment I observed that at 

 first a rapid succession of bubbles ascended into the tube from 

 the incandescent platinum ; it then became quiescent ; the 

 spheroidal state was assumed by the water and no gas 

 ascended ; on losing the spheroidal state a sudden hiss was 

 heard, and a single bubble ascended into the tube. I deter- 

 mined to examine separately the gas from the platinum before 

 and after the quiescent state ; to effect this I placed two in- 

 verted tubes in the capsule, with the orifices near each other ; 

 the platinum at the point of fusion was immersed under one 

 tube, say tube A, and as soon as the ascent of bubbles ceased 

 it was removed across to tube B, and the last bubble then 

 entered that tube ; the gases from each tube were separately 

 analysed, and tube A gave nearly all detonating gas, the resi- 

 due being only 0*2 ; tube B gave none ; the gas collected in it 

 was nitrogen, with a trace of oxygen. 



In order to examine the effect of an oxidable metal under 

 similar circumstances, I fused by the oxyhydrogen blowpipe 

 the end of a stout iron wire, plunged it into prepared water, 

 and collected the globules of gas ; no oxygen was given off, 

 or at least no more than I have always found to accompany 

 hydrogen, which, with a small residue of nitrogen, was the gas 

 given off in this experiment. 



I was now anxious to produce a continuous development 

 of mixed gas from water subjected to heat alone, in other 

 words, to succeed in an experiment which should bear the 

 same relation to Experiment fig. 9 as fig. 5 did to fig. 7 ; for 

 this purpose the apparatus shown at fig. 10 was constructed : 



Y 2 



