We analyze in detail the peculiar velocity field traced by 56 clusters within 120 h \mbox { $ { } ^ { -1 } $ } Mpc in the “ Streaming Motions of Abell Clusters ” ( SMAC ) sample .
The bulk flow of the SMAC sample is 687 \pm 203 km s ^ { -1 } , toward l = 260 \degr \pm 13 \degr , b = 0 \degr \pm 11 \degr .
We discuss possible systematic errors and show that no systematic effect is larger than half of the random error .
The flow does not drop off significantly with depth , which suggests that it is generated by structures on large scales .
In particular , a Great Attractor as originally proposed by Lynden-Bell et al .
can not be responsible for the SMAC bulk flow .
The SMAC data suggest infall into an attractor at the location of the Shapley Concentration , but the detection is marginal ( at the 90 % confidence level ) .
We find that distant attractors in addition to the Shapley Concentration are required to explain the SMAC bulk flow .
A comparison with peculiar velocities predicted from the IRAS PSCz redshift survey shows good agreement with a best fit value of \beta _ { \mathrm { I } } = \mbox { $ \mbox { $ \Omega _ { \mathrm { m } } $ } ^ { 0.6 } $ } / b _ { \mathrm { I } } = % 0.39 \pm 0.17 .
However , the PSCz density field is not sufficient to acount for all of the SMAC bulk motion .
We also detect , at the 98 % confidence level , a residual bulk flow of 372 \pm 127 \ > \mbox { km~ { } s \mbox { $ { } ^ { -1 } $ } } toward l = 273 \degr , b = 6 \degr 
which must be generated by sources not included in the PSCz catalogue , that is , either beyond 200 h \mbox { $ { } ^ { -1 } $ } Mpc , in the Zone of Avoidance or in superclusters undersampled by IRAS .
Finally , we compare the SMAC bulk flow with other recent measurements .
We argue that , at depths ranging from 60 to 120 h \mbox { $ { } ^ { -1 } $ } Mpc , flows of order 600 km s ^ { -1 } are excluded by multiple data sets .
However , convergence to the CMB frame by a depth of 60 h \mbox { $ { } ^ { -1 } $ } Mpc is also excluded by multiple data sets .
We suggest that a bulk flow of 225 \ > \mbox { km~ { } s \mbox { $ { } ^ { -1 } $ } } 
toward l = 300 \degr , b = 10 \degr at depths greater than 60 h \mbox { $ { } ^ { -1 } $ } Mpc is consistent with all peculiar velocity surveys , when allowance is made for sparse sampling effects .