▁kil ns ▁were ▁huge ▁cyl ind rical ▁structures , ▁ 1 5 ▁feet ▁in ▁diameter , ▁and ▁ 2 0 ▁feet ▁in ▁height , ▁with ▁brick ▁walls ▁more ▁than ▁ 3 ▁feet ▁thick . ▁When ▁fired , ▁a ▁kil n ▁used ▁about ▁ 1 0 ▁tons ▁of ▁coal ▁for ▁one ▁firing , ▁with ▁comb ust ion ▁continued ▁for ▁ 3 0 ▁to ▁ 3 5 ▁hours . ▁About ▁ 3 0 , 0 0 0 ▁to ▁ 6 0 , 0 0 0 ▁pieces ▁of ▁w are ▁were ▁included ▁in ▁one ▁firing . ▁ ▁The ▁company ▁appears ▁to ▁have ▁ceased ▁operations ▁in ▁ 1 9 2 2 . ▁ ▁References ▁▁▁ ▁In ▁P urs uit ▁of ▁Beaut y : ▁Americans ▁and ▁the ▁A est h etic ▁Mov ement , ▁Metropolitan ▁Museum ▁of ▁Art , ▁pages ▁ 4 7 5 - 4 7 6 , ▁Jan ▁ 1 , ▁ 1 9 8 6 . ▁ ▁The ▁Gro ve ▁Encyclopedia ▁of ▁Dec or ative ▁Arts , ▁ed . ▁Gordon ▁Campbell , ▁Oxford ▁University ▁Press , ▁ 2 0 0 6 . ▁ ▁" B rie f ▁history ▁of ▁the ▁Union ▁Por cel ain ▁Works ", ▁The ▁Pot tery , ▁G lass ▁& ▁Br ass ▁Sales man , ▁New ▁York , ▁NY , ▁United ▁States , ▁February ▁ 1 5 , ▁ 1 9 1 7 , ▁vol . ▁ 1 5 , ▁no . ▁ 3 , ▁p . ▁ 4 1 - 4 3 , ▁col . ▁ 1 - 2 . ▁