The ornamental design for a carrying harness for a mattress, as shown and described.
FIG. 1 is a top plan view of a carrying harness for a mattress showing my
new design, an intermediate portion of the bottom strap being broken away
and omitted for convenience of illustration;
FIG. 2 is an end elevational view thereof the opposite end being identical
thereto; and
FIG. 3 is a side elevational view thereof the opposite side being identical
thereto.
The partial showing of fabric texture is understood to be continuous on all
surfaces.