The following account of the origin and antiquity of Halcyon Days will,
I feel convinced, prove a valuable addition to that given by your
intelligent correspondent P.T.W., in No. 471 of _The Mirror_:--

Halcyon Days, in antiquity, implied seven days before, and as many
after, the winter solstice--because the halcyon laid her eggs at this
time of the year, and the weather during her incubation being, as
your correspondent observes, usually calm. The phrase was afterwards
employed to express any season of transient prosperity, or of brief
tranquillity--the _septem placidae dies_ of human life:

The winter solstice just elapsed; and now
Silent the season, sad alcyone
Builds near the sleeping wave her tranquil nest.

_Eudosia._


When great Augustus made war's tempest cease,
His halcyon days brought forth the arts of peace.

_Dryden._


The halcyon built her nest on the rocks adjacent to the brink of the
ocean, or, as some maintain, on the surface of the sea itself:

Alcyone compress'd
Seven days sits brooding on her wat'ry nest,