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   PR # 41260
   It is known some clusters of galaxies have arclike images by
   gravitational lens- ing. Now we can derive the mass of clusters from
   their arcs.It reflects the total mass contained in the lensing
   system,independent of the specific matter contents and states.Our
   aimis to compare the dynamical masses from hydrostatic equilibrium
   with the gravitational masses from arclike images of background
   galaxies and to estimate the difference of these two results for
   undestanding the mass distribution of the cluster of galaxies.To
   achieve this aim we will propose the observation of galaxyclusters
   with luminous arcs,MS1455+2232 and MS1910.5+6736.
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