▁over ▁their ▁machines . ▁If ▁children ▁were ▁caught ▁sleep ing ▁or ▁showed ▁up ▁to ▁work ▁late , ▁they ▁were ▁be aten ▁and ▁tort ured ▁by ▁their ▁super vis ors . ▁Such ▁cruel ty ▁was ▁en act ed ▁on ▁children ▁as ▁a ▁result ▁of ▁the ▁drive ▁of ▁master - man ufact ur ers ▁to ▁maintain ▁high ▁output . ▁While ▁it ▁is ▁a ▁common ▁view ▁that ▁some ▁children ' s ▁bodies ▁become ▁cro oked ▁and ▁de formed ▁from ▁their ▁work ▁in ▁the ▁mill s ▁and ▁fact ories ,[ 4 ] ▁it ▁has ▁also ▁been ▁argued ▁that ▁the ▁pre val ence ▁of ▁child hood ▁dise ases ▁in ▁this ▁era ▁made ▁a ▁bigger ▁contribution ▁to ▁de form ity .[ 5 ] ▁ ▁Children ▁in ▁the ▁mines ▁suffered ▁similarly . ▁Both ▁boys ▁and ▁girls ▁would ▁start ▁working ▁at ▁the ▁age ▁of ▁four ▁or ▁five . ▁A ▁size able ▁proportion ▁of ▁children ▁working ▁in ▁the ▁mines ▁were ▁under ▁ 1 3 ▁and ▁a ▁larger ▁proportion ▁were ▁aged ▁ 1 3 - 1 8 . ▁M ines ▁of ▁the ▁era ▁were ▁not ▁built ▁for ▁stability ; ▁rather , ▁they ▁were ▁small ▁and ▁low . ▁Children , ▁therefore , ▁were ▁needed ▁to ▁craw l ▁through ▁them . ▁The ▁conditions ▁in ▁the ▁mines ▁were ▁unsafe , ▁children ▁would ▁often ▁have ▁lim bs ▁cri pp led , ▁their ▁bodies ▁dist orted , ▁or ▁be ▁killed . ▁Children ▁could ▁get ▁lost ▁within ▁the ▁mines ▁for ▁days ▁at ▁a ▁time . ▁The ▁air ▁in ▁the ▁mines ▁was ▁harm ful ▁to ▁bre at he ▁and ▁could