Note 10 — Chapter II · THE COMPOSITION OF WATER, HYDROGEN
George Kamensky translation
The composition of water, as we saw above, was determined by passing steam over red-hot iron; the same method has been used for making hydrogen for filling balloons. An oxide having the composition Fe3O4 is formed in the reaction, so that it is expressed by the equation 3Fe + 4H2O = Fe3O4 + 8H.