The ornamental design for a double candlewick, as shown and described.
FIG. 1 is a perspective view of an embodiment of a double candle wick showing our new design.
FIG. 2 is a front elevation view thereof, the back elevation view being a mirror image thereof, and the side elevation views having the same appearance.
FIG. 3 is a top plan view thereof.
FIG. 4 is a perspective view of the double candle wick of FIGS. 1-3 shown as a component of a wax candle.
FIG. 5 is a side elevation view thereof, shown with the wax removed, the opposite side elevation view being a mirror image thereof; and,
FIG. 6 is a top plan view thereof.
The broken lines in the drawings are included for purposes of illustrating portions of the environment used with the double candle wick that form no part of the claimed design.