A linearity test shows H _ { 0 } to decrease by 7 % out to 18 000 \nobreak \mbox { $ $km s$ { } ^ { -1 } $ } .
The value at 10 000 \nobreak \mbox { $ $km s$ { } ^ { -1 } $ } is a good approximation to the mean value of H _ { 0 } over very large scales .
The construction of the extragalactic distance scale is discussed .
Field galaxies , cluster distances relative to Virgo , and blue supernovae of type Ia yield H _ { 0 } ( cosmic ) with increasing weight ; they give consistently H _ { 0 } = 57 \pm 7 ( external error ) .
This value is supported by purely physical distance determinations ( SZ effect , gravitational lenses , MWB fluctuations ) .
Arguments for H _ { 0 } > 70 are discussed and shown to be flawed .