Note 15 bis — Chapter II · THE COMPOSITION OF WATER, HYDROGEN
George Kamensky translation
If, when the sulphuric acid is poured over the zinc, the evolution of the hydrogen proceed too slowly, it may be greatly accelerated by adding a small quantity of a solution of CuSO4 or PtCl4 to the acid. The reason of this is explained in Chap. XVI., note 10 bis.