Various lines in the spectrum of 9 Sgr observed at two different epochs. The lower spectrum was taken on 10 July 2004 (HJD 2 453 196.586) whilst the uppermost spectrum was obtained on 5 October 2006 (HJD 2 454 013.526). From left to right, these lines illustrate the various behaviours that exist in the spectrum: lines predominantly formed in the atmosphere of the primary (N v λλ 4603, 4620), lines not showing any clear binary signature (He ii λ 5412), lines belonging to the secondary (C iii λ 5696) and lines displaying an SB2 signature (C iv λλ 5801, 5812). In each panel, the dashed red lines indicate the rest wavelengths of the lines.