A Chinese Imperial Porcelain fruit bowl and a cloisonne enamel icebox. [File photo]

Iceboxes made of wood were widely used in the royal court of the Qing Dynasty. Due to the weak conductivity of heat, lead or tin is put inside the box to extend the hours for preserving the natural ice. Many historical materials record emperors, empresses and imperial concubines using the box to keep food like melons and fruits cool in the hot summer days.