  Utilizing ASCA archival data of about 300 objects of elliptical galaxies,
groups, and clusters of galaxies, we performed systematic measurements of the
X-ray properties of hot gas in their systems, and compiled them in this paper.
The steepness of the luminosity--temperature (LT) relation, $L_{\rm
X}\propto(kT)^{\alpha}$, in the range of $kT=$1.5--15 keV is
$\alpha=3.17\pm0.15$, consistent with previous measurements. In the relation,
we find two breaks at around ICM temperatures of 1 keV and 4 keV:
$\alpha=2.34\pm0.29$ above 4 keV, $3.74\pm0.32$ in 1.5--5 keV, and
$4.03\pm1.07$ below 1.5 keV. Such two breaks are also evident in the
temperature and size relation. The steepness in the LT relation at $kT>4$ keV
is consistent with the scale-relation derived from the CDM model, indicating
that the gravitational effect is dominant in richer clusters, while poorer
clusters suffer non-gravity effects. The steep LT relation below 1 keV is
almost attributed to X-ray faint systems of elliptical galaxies and galaxy
groups. We found that the ICM mass within the scaling radius $R_{1500}$ follows
the relation of $M_{\rm gas}\propto T^{2.33\pm0.07}$ from X-ray faint galaxies
to rich clusters. Therefore, we speculate that even such X-ray faint systems
contain a large-scale hot gas, which is too faint to detect.
