Show WIRED WIRELESS USED IN MINES MmES SPRINGFIELD Ill July 26 28 W P Possibility of ot the establish establish- establishment establishment ment of communication between underground mine workers and the tho surface through the tho development ot of the line IIno ra radio lIo or wired wire wireless sire Ire less I Is given further furtner Impetus as the result rosult of ot toots tests conducted In Illinois mines The Tho wired wireless utilizes trolley wire mine tracks 8 corn corn- com compressed pressed presed air and water piping and sImilar conductors for tor trans mission It Is reasonably euro O to Withstand severe sovere disturbances oc- oc oc occasioned b by mine explosions or Ins Ins cave Il according to L J J I ky ky Icy engineer of the tile department ot of the Interior who Is making a spec pec special spec spec- special ial study of ot tlc the matter In tests conducted In a coal callI pino feet deep iMP no difficulty w was ex- ex experienced ex experienced on tl the surface In log ing radio messages from n II set mounted upon a a mine e ns as long lone as the apparatus was In the vicinity ot of o the metallic carrion carriers r show chow that the range In the average coal mine mino i Is only a afew afew afew few hundred feet teet when no con con- conductors con conductors are present but may bo be ovral thousand feet teet a when hen operating operating ing In the tho proximity to metAl car car- cari car i lets nn |