  The entire dataset of the GRANAT/SIGMA observations of Cyg X-1 and
1E1740.7-2942 in 1990-1994 was analyzed in order to search for correlations
between primary observational characteristics of the hard X-ray (40-200 keV)
emission - hard X-ray luminosity, hardness of the spectrum (quantified in terms
of the best-fit thermal bremsstrahlung temperature kT) and the RMS of
short-term flux variations. Although no strict point-to-point correlations were
detected certain general tendencies are evident. It was found that for Cyg X-1
the spectral hardness is in general positively correlated with relative
amplitude of short-term variability. The correlation of similar kind was found
for X-ray transient GRO J0422+32 (X-ray Nova Persei 1992). For both sources an
approximate correlation between kT and L_X was found. At low hard X-ray
luminosity - below 10E37 erg/sec - kT increases with L_X. At higher luminosity
the spectral hardness depends weaker or does not depend at all on the hard
X-ray luminosity. The low luminosity end of these approximate correlations (low
kT and low RMS) corresponds to extended episodes of very low hard X-ray flux
occurred during SIGMA observations.
