As shown in the accompanying figure, the weekly airspace CO2 concentrations of the three experimental units continue to diverge from each other.  Differences in the appearances of the plants are also becoming more distinct.  It is apparent, however, that under the light regime we are using, the radish plants may never produce the bulbous roots for which they are grown commercially.  Nevertheless, we may still obtain a useful result from the study, and so we continue on.