Within an hour of daybreak, when the moon was setting, they were awakened by the wonderful singing of a bird, and they rose for matins and strove not to listen, but so strangely sweet was the sound in the keen moonlight morning that they could not forbear.  The moon set, and still in the dark sang the bird, and the grey light came, and the bird ceased; and when it was white day they saw that all the ground and every stalk of bracken was hoary with frost, and every ivy-leaf was crusted white round the edge, but within the edge it was all glossy green.