  Calibrated Tully-Fisher relations ''absolute magnitude - HI line width'' for
spiral galaxies oriented edge-on are derived from published data. The slope of
the linear fits, especially in R- and I- bands, is close to the value of -10,
as predicted by the theory. The standard errors of the relations in B, V, R and
I bands are 0.40, 0.36, 0.31 and 0.34 mag, corresponding to relative distance
errors of 18%, 17%, 14% and 16%, respectively. The magnitude of an edge-on
galaxy appears to be a good distance indicator.
