This paper aims to reconstruct the history of the first transatlantic wireless telegraphy on the basis of J. A. Fleming's unpublished notebooks and other manuscript sources. It will be shown that the progress of the experiment, in which power engineering was first combined with wireless telegraphy, was neither smooth nor automatic, and various kinds of difficulties or ‘resistances’ that Fleming and Marconi encountered during the course of the experiments in the laboratory and in the field at Poldhu will be emphasized. (...) This paper also aims to compare two different ‘styles’ of engineering. Fleming, whose educational background included Cambridge experimental physics, based his approach upon scientific engineering—that is, laboratory experiments, precise measurement, and mathematical considerations, whereas Marconi's work derived from an older style of doing technology—that is, field experiments, handicraft work, and an intuitive understanding of technological effects. These two different styles clashed in the experiment, and it will be shown that this tension became apparent when credit for a project's success was being assigned. (shrink)