14 
MR. GROVE ON THE DECOMPOSITION OF WATER BY HEAT. 
tioned to Mr. Gassiot, and also to Mr. Bingham my assistant (to whose assiduity 
I am much indebted), that I was inclined to think if water could be absolutely de- 
prived of air, it would be decomposed by heat, a result which I have now attained 
by a totally different series of inductions. It is a circumstance worthy of remark, 
that I find the greater part of the air to be expelled at a comparatively low tempera- 
ture, and when the water has come in contact with the platinum, while the decom- 
position all takes place when the platinum is surrounded by an atmosphere of steam, 
if steam it may be called, for the state of this atmosphere at the first immersion of 
the platinum is at present very mysterious. 
I think I may now safely regard it as proved, that platinum intensely ignited will 
decompose water, and several considerations press on the mind in reflecting on this 
novel phenomenon. 
First of all, to those who are attached to the cui bono argument, and estimate 
physical science in proportion only to its practical applications, I would say that 
these experiments afford some promise of our being, at no distant period, able to 
produce mixed gases for purposes of illumination, &c. by simply boiling water and 
passing it through highly ignited platinum tubes, or by other methods which may be 
devised ; we in fact by this means, as it were, boil water into gas, and there appears 
theoretically no more simple way of producing chemical decomposition. 
To pass however to more important considerations: the spheroidal state, which has 
lately attracted the attention of philosophers, appears to be closely connected with 
these results, and is rendered more deeply interesting. The last experiment but two 
which I have mentioned, shows that the spheroidal state is intermediate between ordi- 
nary ebullition and the decomposing ebullition ; it is probably therefore a state of polar 
tension, coordinate in some respects with that which takes place in the cell of a voltaic 
combination before decomposition, or when the power employed not being of sufficient 
intensity to produce actual decomposition, the state commonly called polarization of 
the electrodes, obtains. The phenomenon brings out also a new relation between 
heat, electricity, and chemical affinity; hitherto many electrical phenomena could be 
produced by heat and chemical action, the difference being that in the effects pro- 
duced by the last two forces there was no polar chain, but every minute portion of 
the matter acted on gave rise to the phenomena which in the electrical effects are 
only observable at the polar extremities ; thus in decomposing water by iron and 
sulphuric acid, or by passing steam over heated tubes of iron, parallel results are 
obtained to the electrolysis of water with an iron anode ; but in the former cases every 
portion of the iron oxidated gives off its equivalent of hydrogen, in the latter the 
equivalent is evolved from the cathode at a point distant from that where the oxida- 
tion takes place. Hitherto electricity has been the only force by which many com- 
pounds, and particularly water, could be resolved into their constituents without either 
of these being absorbed by another affinity. The decomposition by ignited platinum 
removes this exception, and presents the parallel effect produced by heat alone. 
