Complex sentence: He had published some technical papers on applications in electric metallurgy but in 1908 switched interests to wireless communication after investigating a system for voice transmission by spark gap transmitter invented by Francis Joseph McCarty in 1902.
Split into simpler sentences: He had published some technical papers on applications in electric metallurgy. In 1908 he switched interests to wireless communication after investigating a system for voice transmission by spark gap transmitter invented by Francis Joseph McCarty in 1902.