286 NATURAL HISTORY 



it tough and permanent ; with this differ- 

 ence, that whereas the shell of the martin 

 is nearly hemispheric, that of the swallow 

 is open at the top, and like half a deep 

 dish : this nest is lined with fine grasses, 

 and feathers which are often collected as 

 they float in the air. 



Wonderful is the address which this 

 adroit bird shows all day long in ascend- 

 ing and descending with security through 

 so narrow a pass. When hovering over the 

 mouth of the funnel, the vibrations of her 

 wings acting on the confined air occasion 

 a rumbling like thunder. It is not impro- 

 bable that the dam submits to this incon- 

 venient situation so low in the shaft, in 

 order to secure her broods from rapacious 

 birds, and particularly from owls, which 

 frequently fall down chimnies, perhaps in 

 attempting to get at these nestlings. 



The swallow lays from four to six white 

 eggs, dotted with red specks ; and brings 

 out her first brood about the last week in 

 June, or the first week in July. The pro- 

 gressive method by which the young are 



