We report preliminary results from a third sample of quasar absorption line spectra from the Keck telescope which has been studied to search for any possible variation of the fine structure constant , \alpha .
This third sample , which is larger than the sum of the two previously published samples , shows the same effect , and also gives , as do the previous two samples , a significant result .
The combined sample yields a highly significant effect , \mbox { $ \Delta \alpha / \alpha$ } = \left ( \alpha _ { z } - \alpha _ { 0 } \right ) / \alpha _ { 0 } = -0. % 57 \pm 0.10 \times 10 ^ { -5 } , averaged over the redshift range 0.2 < z < 3.7 .
We include a brief discussion of small-scale kinematic structure in quasar absorbing clouds .
However , kinematics are unlikely to impact significantly on the averaged non-zero \Delta \alpha / \alpha above , and we have so far been unable to identify any systematic effect which can explain it .
New measurements of quasar spectra obtained using independent instrumentation and telescopes are required to properly check the Keck results .