Note {306} — Chapter IV · ON THE NUMBER OF INTERMEDIATE FORMS REQUIRED ON THE THEORY OF COMMON DESCENT; AND ON THEIR ABSENCE IN A FOSSIL STATE
Reading edition
In the Essay of 1842 the author uses astronomy in the same manner as an illustration. In the Origin this does not occur; the reference to the action of secondary causes is more general, e.g. Ed. i. p. 488, vi. p. 668.