Intensity predictions of the observed lines as a function of gas temperature normalized to their value at 10 K. The intensities have been calculated by running the model of the Perseus cloud presented in Paper I for 12 different gas temperatures. For each temperature, six different H₂ column densities in the range 2 × 10²¹ to 2 × 10²³ cm⁻² have been assumed, and each circle represents the intensity average with an error bar that indicates the 1σ dispersion (and is often smaller than the marker size). The upper block of panels contains the CO isotopologs, the middle block contains the traditional dense-gas tracers and their isotopologs, and the bottom panel contains N₂H⁺(1−0). The solid red lines represent the empirical fits described in the text and used in the analysis to correct for gas temperature variations. The dashed black; lines in the CO and C¹⁸O panels represent the optically thick and thin LTE solutions discussed in the text.