Halcyon-days denote a time of peace and tranquillity. The expression
takes its rise from a sea-fowl, called among naturalists _halcyon_,
or _alcyon,_ which is said to build its nest about the winter
solstice, when the weather is usually observed to be still and calm.
Aristotle and Pliny tell us that this bird is most common in the seas of
Sicily, that it sat only a few days, and those in the depth of winter,
and during that period the mariner might sail in full security; for
which reason they were styled _Halcyon-days_.