220 History of Nature. [BooK X. 



the greater Part of a Sky-blue Colour, yet with white and 

 purple Feathers intermingled, and having a long and slender 

 Neck. There is another Kind of them that differs in size 

 and Song. The lesser sing among the Reeds. It is very 

 rare to see an Halcyon, and never except at the setting of 

 Virgilise, or about the Solstices or Mid-winter; for some- 

 times they fly about a Ship, but immediately they go into 

 Concealment. They breed in Mid-winter, and the Days 

 when this is are called the Halcyon Days : for while they 

 last, the^Sea is calm and navigable, especially in Sicily. In 

 other Parts, also, the Ocean is not so boisterous ; but surely 

 the Sicilian Sea is navigable, both in the Straits and the 

 open Ocean. Now, seven Days before Mid-winter they build 

 their Nests; and within as many after, they have hatched. 

 Their Nests are wonderfully made, in the shape of a Ball : 

 the Entrance narrow, and standing somewhat out, much 

 like that of great Sponges. They cannot be cut asunder with 

 an iron Instrument ; but they will break with a strong Blow, 

 like the dry Foam of the Sea : and no Man could ever find 

 of what they are made. Some think they are formed of the 

 sharp pointed Prickles of Fishes; for these Birds live on 

 Fish. They come up also into Rivers. They lay five Eggs. 

 The Gaviae 1 build in Rocks: and the Mergus 2 also in 

 Trees. They usually lay four Eggs : but the Gavite in 

 Summer, the Mergi in the beginning of Spring. 



CHAPTER XXXIII. 



Of the Skill of Birds in building their Nests. Of the 

 Hirundo, 3 the Argatilis, Cinnamologus, and Perdix. 



THE Form of the Halcyon's Nest puts me in mind of the 

 Skill of other Birds : and in no other Thing is the Ingenuity 



1 A general name for all the Gulls. Wern. Club. 



2 Mergus merganser, LINN. Goosander. Wern. Club. 



3 The first, H. rustica, LINN.; Chimney Swallow. Second: H. wlica, 

 LINN. ; House Martin. The third : H. riparia, Bank Martin. The story 

 of an embankment of the Nile formed by Martins' nests, must be set down 

 among the Wonders of Egypt. Wern. Club. 



