The following condensed account has been abstracted from it.
It seemed to Herschel that he was thus able to view the actual changes by which masses of phosphorescent or glowing vapour became actually condensed down into stars.
This may be brought about by a distillation under pressure, or by allowing the condensed distillate to fall into the highly heated residue in the still.
Such condensed nuclei are, in many cases, more readily obtained than the parent nucleus.
Naphthyridines and naphthinolines result from the condensation of two pryridine and two quinoline nuclei respectively; and quino-quinolines are unsymmetrical naphthyridine nuclei condensed with a benzene nucleus.
