Scatter plot of I([C ii]) versus I(H i) for all [C ii] sources. The straight lines are predicted I([C ii]) for low density atomic H i diffuse clouds as a function of I(H i) (which is proportional to the H i column density) for four different characteristic pressures from P = 2000 K cm^-3 to 6000 K cm^-3. This pressure range covers predicted values for the diffuse clouds from R_gal ~ 10 kpc to ~4 kpc, with 3000 K cm^-3 characteristic of the solar radius. It is clear that the vast majority of the GOT C+ [C ii] sources require an additional source of [C ii] emission other than the diffuse atomic gas. The 1-σ noise for I([C ii]) is indicated on three representative low intensity points; those for I(H i) are too small to be visible on this figure and have been omitted. It can be seen on the scale of this figure that the S/N is high for most of points in this scatter plot.