Page [28], printer's error, missing full stop at end of sentence added, ['in the case of the hammer break.'].

Page [33], printer's error, supppse for suppose, ['Let us supppse'].

Page [46], printer's error, comma rather than full stop at end of sentence, ['to the transmitting aerial,'].

Page [48], possible printer's error, alterations for alternations, ['alterations of electric strain'].

Page [54], printer's error, Banly for Branly, ['proved that in a Banly tube,'].

Page [56], variation in spelling, unsensitive for insensitive, ['wounded and unsensitive.'].

Page [59], possible printer's error, sensive for sensitive ['to work a sensive recording apparatus'].

Page [59], possible printer's error, arragement for arrangement, ['most interesting arragement'].

Page [61], printer's error, missing letter i, ['as shown n Fig. 18,'].

Page [71], printer's error, osciilating for oscillating, ['to that of the osciilating circuit'].