▁These ▁first ▁engines ▁were ▁used ▁to ▁power ▁p umps ▁and ▁produced ▁only ▁reci proc ating ▁motion ▁to ▁move ▁the ▁p ump ▁ro ds ▁at ▁the ▁bottom ▁of ▁the ▁sh aft . ▁The ▁design ▁was ▁commer cially ▁successful , ▁and ▁for ▁the ▁next ▁five ▁years ▁W att ▁was ▁very ▁busy ▁installing ▁more ▁engines , ▁mostly ▁in ▁Corn wall ▁for ▁p ump ing ▁water ▁out ▁of ▁mines . ▁ ▁These ▁early ▁engines ▁were ▁not ▁manufact ured ▁by ▁B oul ton ▁and ▁W att , ▁but ▁were ▁made ▁by ▁others ▁according ▁to ▁draw ings ▁made ▁by ▁W att , ▁who ▁served ▁in ▁the ▁role ▁of ▁consult ing ▁engineer . ▁The ▁ere ction ▁of ▁the ▁engine ▁and ▁its ▁sh aked own ▁was ▁super vised ▁by ▁W att , ▁at ▁first , ▁and ▁then ▁by ▁men ▁in ▁the ▁firm ' s ▁employ . ▁These ▁were ▁large ▁machines . ▁The ▁first , ▁for ▁example , ▁had ▁a ▁cyl inder ▁with ▁a ▁diameter ▁of ▁some ▁ 5 0   in ches ▁and ▁an ▁overall ▁height ▁of ▁about ▁ 2 4 ▁feet , ▁and ▁required ▁the ▁construction ▁of ▁a ▁dedicated ▁building ▁to ▁house ▁it . ▁B oul ton ▁and ▁W att ▁charged ▁an ▁annual ▁payment , ▁equal ▁to ▁one ▁third ▁of ▁the ▁value ▁of ▁the ▁coal ▁saved ▁in ▁comparison ▁to ▁a ▁New com en ▁engine ▁performing ▁the ▁same ▁work . ▁ ▁The ▁field ▁of ▁application ▁for ▁the ▁in vention ▁was ▁greatly ▁w iden ed ▁when ▁B oul ton ▁ur ged ▁W att ▁to ▁convert ▁the ▁reci proc ating ▁motion ▁of ▁the