members as at 15 16 17 and 18 in fig3 the longitudinal wire members 15 18 lie longitudinally along the frustum of a cone and converge from left to right as seen in fig3 having their more spaced ends secured to an end ring or band 19 at the relatively large body end 12 and having their lesser spaced ends secured to a smaller end ring or band 20 at the smaller body end 13 the longitudinal wire members are secured about approximately one half of each end band 19 and 20 a plurality of generally parallel arcuate wire members 21 22 and 23 lie on the frustum of a cone in transverse planes thereof and are welded or otherwise secured at crossing regions to the longitudinal wire members the arcuate wire members 21 23 are generally semicircular and arranged in parallel spaced relation at substantially equal intervals between the end bands 19 and 20 the hereinbefore described lower longitudinal wire members 15 18 extending between and secured to the end bands 19 and 20 and the generally semicircular arcuate transverse wire members 21 23 combine to define a generally semifrusto conical tubular section 25 being the lower longitudinal section in the illustrated embodiment an upper longitudinal semifrusto conical section 26 includes a plurality of longitudinal members or wires 35 36 37 and 38 lying longitudinally along the same frustum of a cone as the longitudinal members 15 18 however the upper longitudinal members 35 38 have their opposite end terminating just short of and free from the end rings 19 and 20 as seen in fig3 securing together the several longitudinal members 35 38 are a plurality of.