1 rich Libsyn https://www.libsyn.com 90 600 u/EdHistory101 talks to Robert E.C. Davis about his book on the US Army Heliograph Networks in the American South. (38 minutes)&amp;nbsp; The AskHistorians Podcast http://www.reddit.com/r/AskHistorians/wiki/podcast <iframe title="Libsyn Player" style="border: none" src="//html5-player.libsyn.com/embed/episode/id/42875870/height/90/theme/custom/thumbnail/yes/direction/forward/render-playlist/no/custom-color/ff5700/" height="90" width="600" scrolling="no" allowfullscreen webkitallowfullscreen mozallowfullscreen oallowfullscreen msallowfullscreen></iframe> https://assets.libsyn.com/secure/item/42875870