▁by ▁Benjamin ▁Franklin ▁and ▁other ▁French ▁scient ists ▁to ▁fin ance ▁further ▁experiments ▁but ▁was ▁not ▁able ▁to ▁raise ▁enough ▁money ▁to ▁go ▁ahead . ▁The ▁British ▁util itar ist ▁philosoph ▁Jer emy ▁Bent ham ▁proposed ▁the ▁inclusion ▁of ▁" con vers ation ▁tub es " ▁in ▁the ▁architecture ▁of ▁his ▁P ano pt icon ▁( 1 7 8 7 , ▁ 1 7 9 1 , ▁ 1 8 1 1 ) ▁and ▁then ▁as ▁military ▁tele communic ation ▁mean ▁( 1 7 9 3 ) ▁and ▁at ▁the ▁end ▁as ▁a ▁necessary ▁equipment ▁in ▁the ▁architecture ▁of ▁Min ist ries ▁( 1 8 2 5 ) ▁▁ ▁While ▁its ▁most ▁common ▁use ▁was ▁in ▁int ra - ship ▁communic ations , ▁the ▁principle ▁was ▁also ▁used ▁in ▁aff lu ent ▁homes ▁and ▁offices ▁of ▁the ▁ 1 9 th ▁century , ▁as ▁well ▁as ▁expensive ▁ ▁autom ob iles , ▁military ▁aircraft , ▁and ▁even ▁locomot ives . ▁For ▁most ▁purposes , ▁the ▁device ▁was ▁out mod ed ▁by ▁the ▁tele phone ▁and ▁its ▁w ides p read ▁ad option . ▁ ▁Design ▁ ▁Early ▁voice pip es ▁consisted ▁of ▁two ▁con es , ▁of ▁wood ▁or ▁metal , ▁one ▁end ▁sh aped ▁to ▁fit ▁the ▁speaker ' s ▁mouth , ▁connected ▁to ▁the ▁other ▁which ▁was ▁fla red ▁to ▁ampl ify ▁the ▁sound ▁( specific ally ▁to ▁match ▁the ▁imped ance ▁of ▁the ▁t ube ▁to ▁that ▁of ▁the ▁open ▁room ). ▁Later ▁designs ▁of ▁the ▁voice pipe ▁inserted ▁a