A FEW months ago, K. Peters and I published an account of experiments we had made in an attempt to transmute hydrogen into helium (Ber. d. Deutschen Chem. Ges., 59, 2039; 1926). A more or less detailed account of this publication appeared in the columns of NATURE (vol. 118, p. 526, 1926), and perhaps I may be permitted to refer to a more recent publication on the same topic by K. Peters, P. Günther, and myself (Ber. d. Deutschen Chem. Ges., 60, 808; 1927). In this communication, as a result of further experiments, we feel that we are in a position to give an explanation of the occurrence of the observed very small quantities of helium in our experiments, without having recourse to the assumption of a synthesis of helium.