242 ON VARIOUS FARTS 



nor do any insects appear for their support. 

 That they can retire to rest, and sleep away 

 these uncomfortable periods as bats do, is a^ 

 matter rather to be suspected than proved : 

 or do they not rather spend their time in 

 deep and sheltered vales near waters, where 

 insects are more likely to be found ? Cer- 

 tain it is, that hardly any individuals of 

 this genus have at such times been seen 

 for several days together. 



September 13, 1791. The congregating 

 flocks of hirundines on the church and 

 tower are very beautiful and amusing I 

 When they fly off together from the roof^ 

 on any alarm, they quite swarm in the air. 

 But they soon settle in heaps, and preening 

 their feathers, and lifting up their wings to 

 admit the sun, seem highly to enjoy the 

 warm situation. Thus they spend the heat 

 of the day, preparing for their emigration^ 

 and, as it were, consulting when and where 

 they are to go. The flight about the 

 church seems to consist chiefly of house 

 martins^ about 400 in number : but ihevf 



