 Knapen , who had previously worked on systems for removing moisture from buildings , was in turn inspired by Chaptal 's work and he set about building an ambitiously large puits aerien ( aerial well ) on a 180 metres ( 590 ft ) high hill at Trans @-@ en @-@ Provence in France . Beginning in 1930 , Knapen 's dew tower took 18 months to build ; it still stands today , albeit in dilapidated condition . At the time of its construction , the condenser excited some public interest . 
