158 THE NATURAL HISTORY 



as nature seldom works in vain, martins will breed on for 

 several years together in the same nest, where it happens 

 to be well sheltered and secure from the injuries of 

 weather. The shell or crust of the nest is a sort of rustic 

 work full of knobs and protuberances on the outside : 

 nor is the inside of those that I have examined smoothed 

 with any exactness at all ; but is rendered soft and warm, 

 and fit for incubation, by a lining of small straws, grasses, 

 and feathers ; and sometimes by a bed of moss interwoven 

 with wool. In this nest they tread, or engender, fre- 

 <juently during the time of building ; and the hen lays 

 from three to five white eggs. 



At first when the young are hatched, and are in a 

 naked and helpless condition, the parent birds, with 

 tender assiduity, carry out what comes away from their 

 young. Was it not for this affectionate cleanliness the 

 nestlings would soon be burnt up, and destroyed in so 

 <leep and hollow a nest, by their own caustic excrement. 

 In the quadruped creation the same neat precaution is 

 made use of ; particularly among dogs and cats, where 

 the dams lick away what proceeds from their young. But 

 in birds there seems to be a particular provision, that the 

 dung of nestlings is enveloped into a tough kind of jelly, 

 and therefore is the easier conveyed oft without soiling 

 or daubing. Yet, as nature is cleanly in all her ways, 

 the young perform this office for themselves in a little 

 time by thrusting their tails out at the aperture of their 

 nest. As the young of small birds presently arrive at 

 their rfKiKM or full growth, they soon become impatient 

 ■of confinement, and sit all day with their heads out at the 

 orifice, where the dams, by clinging to the nest, supply 

 them with food from morning to night. For a time the 

 young are fed on the wing by their parents ; but the 

 feat is done by so quick and almost imperceptible a 

 ■sleight, that a person must have attended very exactly to 



