In early pressed glass production, before molds were made for larger pieces, forms such as compotes, lamps & other tall items were pressed in two separate pieces and then fastened together with 'wafer' of molten glass.     The bottom piece was set down, a 'dollop' of molten glass was dropped on it and then the top piece was pressed into the molden drop which by now was the shape of a wafer.      When the glass cooled, the two pieces were joined as one.  Voila!!!!