184 NATURAL HISTORY 



the start, in hatching, of those that build new, by ten days 

 or a fortnight. These industrious artificers are at their 

 labours in the long days before four in the morning : when 

 they fix their materials, they plaster them on with their 

 chins, moving their heads with a quick vibratory motion. 

 They dip and wash as they fly sometimes in very hot 

 weather, but not so frequently as swallows. It has been 

 observed that martins usually build to a north-east or north- 

 west aspect, that the heat of the sun may not crack and 

 destroy their nests : but instances are also remembered 

 where they bred for many years in vast abundance in a hot 

 stifled inn-yard, against a wall facing to the south. 



Birds in general are wise in their choice of situation : but 

 in this neighbourhood, every summer, is seen a strong 

 instance to the contrary at a house without eaves in an 

 exposed district, where some martins build year by year in 

 the corners of the windows. But, as the corners of these 

 windows (which face to the south-east and south-west) are 

 too shallow, the nests are washed down every hard rain; 

 and yet these birds drudge on to no purpose from summer 

 to summer, without changing their aspect or house. It is 

 a piteous sight to see them labouring when half their nest 

 is washed away, and bringing dirt " generis lapsi sarcire 

 ruinas" Thus is instinct a most wonderfully unequal 

 faculty : in some instances so much above reason, in other 

 respects so far below it ! Martins love to frequent towns, 

 especially if there are great lakes and rivers at hand ; nay, 

 they even affect the close air of London. And I have not 

 only seen them nesting in the Borough, but even in the 

 Strand and Fleet Street ; but then it was obvious from the 

 dinginess of their aspect that their feathers partook of the 

 filth of that sooty atmosphere. Martins are by far the least 

 agile of the four species ; their wings and tails are short, 

 and therefore they are not capable of such surprising turns 

 and quick and glancing evolutions as the swallow. Accord- 

 ingly they make use of a placid easy motion in a middle 

 region of the air, seldom mounting to any great height, and 

 never sweeping long together over the surface of the ground 

 or water. They do not wander far for food, but affect 



