Lines observed with the CSO 10.4-m in comet 21P: HCN(3–2) at 265 886.434 MHz on 10–14 November 1998 UT, and CH₃OH lines at 307 165.911 MHz (Upper Side Band, left upper axis scale) and 304 208.324 MHz (Image and Lower Side Band, right upper axis scale) on 14.3 November 1998 UT. The receiver tuning was adjusted in order to get those two methanol line in the same spectrum separated by 20 MHz. The vertical scale is the main beam brightness temperature and the horizontal scale is the Doppler velocity in the comet rest frame. The frequency range of 40.7 MHz for the CH₃ OH spectrum corresponds to a 40 km s⁻¹ Doppler velocity window as for HCN. A velocity scale centred on each line has been plotted on the lower axis of the methanol spectrum.