▁goods , ▁which ▁were ▁then ▁sh ipped ▁to ▁West ▁Africa , ▁where ▁they ▁were ▁bar tered ▁for ▁slaves . ▁The ▁slaves ▁were ▁then ▁brought ▁back ▁to ▁the ▁Car ib bean ▁to ▁be ▁sold ▁to ▁sugar ▁plan ters . ▁The ▁prof its ▁from ▁the ▁sale ▁of ▁the ▁slaves ▁were ▁then ▁used ▁to ▁buy ▁more ▁sugar , ▁which ▁was ▁sh ipped ▁to ▁Europe . ▁ ▁France ▁found ▁its ▁sugar c ane ▁islands ▁so ▁valuable ▁that ▁it ▁effectively ▁trad ed ▁its ▁portion ▁of ▁Canada , ▁fam ously ▁dub bed ▁" a ▁few ▁acres ▁of ▁snow ", ▁to ▁Britain ▁for ▁their ▁return ▁of ▁Gu adel oupe , ▁Martin ique ▁and ▁St . ▁Lu cia ▁at ▁the ▁end ▁of ▁the ▁Seven ▁Years ' ▁War . ▁The ▁Dutch ▁similarly ▁kept ▁Sur in ame , ▁a ▁sugar ▁col ony ▁in ▁South ▁America , ▁instead ▁of ▁seeking ▁the ▁return ▁of ▁the ▁New ▁Netherlands ▁( New ▁York ). ▁ ▁Bo iling ▁houses ▁in ▁the ▁ 1 7 th ▁through ▁ 1 9 th ▁centuries ▁converted ▁sugar c ane ▁ju ice ▁into ▁raw ▁sugar . ▁These ▁houses ▁were ▁attached ▁to ▁sugar ▁plant ations ▁in ▁the ▁Western ▁colon ies . ▁S la ves ▁often ▁ran ▁the ▁bo iling ▁process ▁under ▁very ▁poor ▁conditions . ▁Rect angular ▁boxes ▁of ▁brick ▁or ▁stone ▁served ▁as ▁furn aces , ▁with ▁an ▁opening ▁at ▁the ▁bottom ▁to ▁sto ke ▁the ▁fire ▁and ▁remove ▁as hes . ▁At ▁the ▁top ▁of ▁each ▁furn ace ▁were ▁up ▁to ▁seven ▁co pper ▁k ett les ▁or ▁bo ilers , ▁each ▁one