Physics in Relation to Wireless^*

Abstract

THE preparatory research work for the transmitting station, that is, for generating electromagnetic waves, was done by Hertz in the years 1885–88, and appears to have been prompted by the rivalry between the extant theories of electricity and magnetism. The laboratory work for the receiving station was done by Lodge in 1889, by Minchin and by Branly in 1890. Lodge's work on the reception of electric waves arose from observing that two metal knobs nearly in contact cohered when a spark occurred near them; Minchin's work was on light sensitive cells and his observations of the effects of electric waves was a side issue, but was duly recorded; Branly's investigations were on the diminution of the electrical resistance of contacts between oxidised metals and in masses of filings when sparks were made near by.