Incalmo, in Venetian dialect literally means "graft" as in joining two plants. Think of a vase whose bottom-half is one color and top is another. The glass artist blows two separate bubbles of glass, opens them and joins them together to form a single bubble. It is a difficult operation because the two open lips must be exactly the same size to join properly.
Blown Glass Vase with Encased Decoration; Incalmo Technique, Peach and Primrose Yellow; Topaz foot, Dimensions: 14" x 10"