  The Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft
obtains high resolution spectra of the solar atmosphere in two wavelength
ranges: 170 - 210 and 250 - 290 angstroms. These wavelength regions contain a
wealth of emission lines covering temperature regions from the
chromosphere/transition region (e.g., He II, Si VII) up to flare temperatures
(Fe XXIII, Fe XXIV). Of particular interest for understanding coronal heating
is a line of Ca XVII at 192.858 angstroms, formed near a temperature of 6
million degrees. However, this line is blended with two Fe XI and six O V
lines. In this paper we discuss a specific procedure to extract the Ca XVII
line from the blend. We have performed this procedure on the raster data of
five active regions and a limb flare, and demonstrated that the Ca XVII line
can be satisfactorily extracted from the blend if the Ca XVII flux contributes
to at least ~10% of the blend. We show examples of the high-temperature corona
depicted by the Ca XVII emission and find that the Ca XVII emission has three
morphological features in these active regions -- 1) `fat' medium-sized loops
confined in a smaller space than the 1 million degree corona, 2) weaker,
diffuse emission surrounding these loops that spread over the core of the
active region, and 3) the locations of the strong Ca XVII loops are often weak
in line emission formed from the 1 million degree plasma. We find that the
emission measure ratio of the 6 million degree plasma relative to the cooler 1
million degree plasma in the core of the active regions, using the Ca XVII to
Fe XI line intensity ratio as a proxy, can be as high as 10. Outside of the
active region core where the 1 million degree loops are abundant, the ratio has
an upper limit of about 0.5.
