▁the ▁spring ▁of ▁ 1 8 2 4 . ▁While ▁not ▁a ▁professional ▁aer onaut , ▁he ▁may ▁have ▁planned ▁to ▁become ▁one . ▁ ▁In ▁ 1 8 2 3 , ▁Harris ▁made ▁successful ▁experiments ▁on ▁the ▁River ▁Th ames ▁with ▁a ▁view ▁to ▁prevent ing ▁ships ▁from ▁being ▁struck ▁by ▁light ning . ▁ ▁Harris ▁invent ed ▁the ▁first ▁mechanism ▁for ▁empty ing ▁a ▁bal lo on ▁can opy ▁of ▁gas ▁or ▁hot ▁air , ▁thus ▁reducing ▁the ▁drag ▁on ▁landing . ▁He ▁designed ▁a ▁double ▁val ve , ▁located ▁at ▁the ▁top ▁of ▁the ▁bal lo on ▁bag , ▁with ▁a ▁small ▁val ve ▁fitted ▁inside ▁a ▁larger ▁one . ▁One ▁was ▁for ▁re le asing ▁the ▁g ases ▁slowly , ▁the ▁other ▁quickly . ▁Harris ▁commented ▁that ▁" The ▁science ▁of ▁aer ost ation ▁has ▁l ately ▁fallen ▁into ▁much ▁decay ▁and ▁been ▁the ▁subject ▁of ▁rid ic ule ▁through ▁the ▁total ▁want ▁of ▁in vention ". ▁ ▁Death ▁ ▁Harris ▁died ▁while ▁flying ▁the ▁bal lo on ▁Royal ▁George ▁from ▁V aux hall , ▁London , ▁on ▁ 2 5 ▁May ▁ 1 8 2 4 . ▁An ▁account ▁of ▁his ▁death ▁is ▁given ▁by ▁L . ▁T . ▁C . ▁Rol t , ▁who ▁states ▁that ▁it ▁is ▁likely ▁that ▁as ▁gas ▁gradually ▁escaped ▁from ▁the ▁bal lo on , ▁the ▁cord ▁connecting ▁the ▁gas ▁dis charge ▁val ve ▁to ▁the ▁g ond ola ▁tight ened , ▁re le asing ▁more ▁gas . ▁In ▁the ▁resulting ▁crash