8 2 9 , ▁ranking ▁ 1 3 th ▁of ▁ 4 6 ▁cad ets , ▁and ▁was ▁appointed ▁a ▁second ▁lieutenant ▁in ▁the ▁ 4 th ▁U . S . ▁Art illery . ▁He ▁would ▁become ▁the ▁first ▁West ▁Point ▁gradu ate ▁to ▁be ▁promoted ▁to ▁a ▁general ▁officer ▁in ▁the ▁regular ▁army , ▁reaching ▁a ▁higher ▁rank ▁in ▁the ▁U . S . ▁Army ▁than ▁did ▁his ▁ 1 8 2 9 ▁class mate , ▁Robert ▁E . ▁Lee ▁( 2 nd ▁of ▁ 4 6 ). ▁ ▁U . S . ▁Army ▁service ▁John ston ▁res igned ▁from ▁the ▁Army ▁in ▁March ▁ 1 8 3 7 ▁and ▁studied ▁civil ▁engineering . ▁During ▁the ▁Second ▁Sem in ole ▁War , ▁he ▁was ▁a ▁civil ian ▁top ographic ▁engineer ▁ab o ard ▁a ▁ship ▁led ▁by ▁William ▁Pope ▁Mc Ar thur . ▁On ▁January ▁ 1 2 , ▁ 1 8 3 8 , ▁at ▁Jup iter , ▁Florida , ▁the ▁sail ors ▁who ▁had ▁gone ▁ash ore ▁were ▁attacked . ▁John ston ▁said ▁there ▁were ▁" no ▁less ▁than ▁ 3 0 ▁bullet ▁holes " ▁in ▁his ▁cl othing ▁and ▁one ▁bullet ▁cre ased ▁his ▁scal p , ▁leaving ▁a ▁scar ▁he ▁had ▁for ▁the ▁rest ▁of ▁his ▁life . ▁Having ▁encountered ▁more ▁combat ▁activities ▁in ▁Florida ▁as ▁a ▁civil ian ▁than ▁he ▁had ▁previously ▁as ▁an ▁art illery ▁officer , ▁John ston ▁decided ▁to ▁re join ▁the ▁Army . ▁He ▁depart ed ▁for ▁Washington , ▁D . C .,