. ▁In ▁the ▁st air well ▁opposite ▁the ▁vest ib ule ▁is ▁a ▁grand ▁mar ble ▁and ▁tim ber ▁st air case , ▁square ▁in ▁plan ▁and ▁wrapped ▁around ▁a ▁central ▁void . ▁ ▁The ▁st air well ▁occup ies ▁the ▁tower ▁that ▁termin ates ▁in ▁the ▁roof ▁top ▁bel ved ere . ▁A ▁primarily ▁tim ber ▁structure , ▁the ▁st air ▁has ▁orn amental ▁bal ust ers , ▁car ved ▁string ers ▁and ▁mar ble ▁t read s ▁and ▁ris ers ▁on ▁the ▁fl ights ▁between ▁ground ▁and ▁first ▁floor . ▁P aint ed ▁cast ▁iron ▁pan els ▁are ▁incorpor ated ▁into ▁the ▁st air ▁bal ust rade . ▁Bey ond ▁the ▁first ▁floor ▁the ▁st air ▁t read s ▁and ▁ris ers ▁are ▁tim ber . ▁A ▁nar ro wer ▁st air ▁connect s ▁the ▁second ▁floor ▁to ▁a ▁room ▁at ▁the ▁top ▁of ▁the ▁tower ▁under ▁the ▁bel ved ere . ▁ ▁The ▁upper ▁floor ▁levels ▁are ▁similar ▁in ▁plan ▁to ▁the ▁ground ▁floor ▁with ▁rows ▁of ▁rooms ▁accessed ▁from ▁a ▁central ▁cor rid or . ▁Some ▁larger ▁rooms , ▁such ▁as ▁a ▁former ▁library ▁on ▁the ▁first ▁floor ▁level , ▁occup y ▁the ▁full ▁width ▁of ▁the ▁building ▁and ▁open ▁onto ▁both ▁the ▁ar cade ▁on ▁the ▁western ▁side ▁and ▁the ▁eastern ▁ver and ah . ▁Inter ior ▁walls ▁are ▁generally ▁m ason ry ▁with ▁a ▁pl aster ▁finish . ▁Some ▁ce il ings ▁in ▁larger ▁rooms ▁are ▁pressed ▁metal . ▁The ▁first ▁floor ▁level ▁of ▁the ▁ar cade