PRUNING THE LYMAN-ALPHA FOREST OF Q1331+170

We present a study of the Lyman alpha forest of the QSO 1331 + 170 in the range 1.67 <z(abs) < 2.10 at 18 km s(-1) resolution. Our analysis includes a careful search for previously unidentified heavy-element sy stems, and incorporates detailed deblending of Ly alpha forest lines f rom heavy-element lines. Various statistical properties of Ly alpha fo rest lines, such as distributions of equivalent widths, HI I column de nsities, Doppler parameters and pair-velocity separations, are compute d. The effect on these properties of employing different limiting appr oaches to heavy-element deblending, and profile-fitting of the lines, is illustrated. Our data suggest that the N-HI distribution may not be fitted adequately by a single power law, i.e., that there may be a re lative deficit of strong lines as compared with the predictions of a s ingle power law. However, larger samples are required to verify this d eficit. The median b value is approximate to 32 km s(-1). No significa nt correlation is observed between N-HI and b. An excess on the scale of similar to 100 km s(-1) is seen in the pair-velocity correlations, at the level of similar to 2.6 sigma for the conservative sample and a t the level of similar to 4.9 sigma for the less conservative sample. Marginal excess correlation is seen in both the samples at the greater than or similar to 2 sigma level on scales of similar to 800-1000 km s(-1), and also on scales of similar to 6000 km s(-1).