  We present an analysis of Chandra observations of two high-redshift clusters
of galaxies, ClJ1113.1-2615 at z=0.725 and ClJ0152.7-1357 at z=0.833. We find
ClJ1113 to be relaxed with kT=4.3^{+0.5}_{-0.4}keV and a mass (within the
virial radius) of 4.3^{+0.8}_{-0.7}*10^{14}Msol. ClJ0152, by contrast, is
resolved into a northern and southern subcluster, each massive and X-ray
luminous, in the process of merging. The temperatures of the subclusters are
found to be 5.5^{+0.9}_{-0.8}keV and 5.2^{+1.1}_{-0.9}keV respectively, and
their respective masses are 6.1^{+1.7}_{-1.5}*10^{14}Msol and
5.2^{+1.8}_{-1.4}*10^{14}Msol within the virial radii. 2D modelling of the
X-ray surface brightness reveals excess emission between the subclusters;
suggestive, but not conclusive evidence of a shock front.
  We make a first attempt at measuring the cluster M-T relation at z~0.8, and
find no evolution in its normalisation, supporting the previous assumption of
an unevolving M-T relation. We also find little or no evolution in the L-T
relation, the gas fraction-T relation, the beta-T relation or the metallicity.
These results suggest that, in at least some massive clusters, the hot gas was
in place, and containing its metals, at z~0.8.
  We also highlight the need to correct for the degradation of the Chandra ACIS
low energy quantum efficiency in high-redshift cluster studies when the low
energy absorption is often assumed to be the Galactic value, rather than
measured.
