 To verify his hypothesis Zibold constructed a stone @-@ pile condenser at an altitude of 288 metres ( 945 ft ) on mount Tepe @-@ Oba near the ancient site of Theodosia . Zibold ’ s condenser was surrounded by a wall 1 metre ( 3 ft 3 in ) high , 20 metres ( 66 ft ) wide , around a bowl @-@ shaped collection area with drainage . He used sea stones 10 – 40 centimetres ( 3 @.@ 9 – 15 @.@ 7 in ) in diameter piled 6 metres ( 20 ft ) high in a truncated cone that was 8 metres ( 26 ft ) in diameter across the top . The shape of the stone pile allowed a good air flow with only minimal thermal contact between the stones . 
