of seal bristles 18 is retained between a low pressure backing plate 60 and a spacer plate 62 whereas the bundle 58 is retained between a second spacer plate 64 and a high pressure backing plate 66 as in the embodiment of fig6 the bristles 18 of each bundle 56 58 need not be connected to a shoe 34 axial rigidity and radial compliance are provided primarily by a spring element 68 connected between the low pressure backing plate 60 and shoe 34 and a second spring element 70 connected between the high pressure backing plate 66 and the shoe 34 referring now to fig8 and 9 a still further embodiment of a seal 72 according to this invention is shown the seal 72 is similar to that of seals 40 and 55 except for the spring elements 74 each spring element 74 is essentially a rectangular shaped beam with an outer band 76 radially spaced from an inner band 78 one end of each of the bands 76 and 78 is connected to a seat 80 formed in the stator 12 and the opposite end of bands 76 78 mounts to a ridge 82 formed in a shoe 34 the spring element 74 functions to maintain the shoe 34 in sealing relationship with the rotor 14 in the same manner as the spring elements 52 and 68 70 a bundle 72 of seal bristles 18 is fixed at its outer end to the stator 12 and the inner end of each seal bristle 18 extends toward the shoe 34 where it may or may not be affixed thereto in each of the embodiments of fig6 9 the seal bristles 18 form essentially a secondary seal the.