106 NATURAL HISTORY 



pleasant ; but in so complicated a way 

 becomes whimsical and unnatural, and 

 liable to the objection due to him, 



" Qui variare cupit rem prodigialiter unam." 



I am, &c. 



LETTER LV. 



TO THE SAME. 



DEAR SIR ; October 10, 1781. 



I THINK I have observed before that much 

 the most considerable part of the house- 

 martins withdraw from hence about the 

 first week in October; but that some, the 

 latter broods I am now convinced, linger 

 on till towards the middle of that month ; 

 and that at times, once perhaps in two or 

 three years, a flight, for one day only, has 

 shown itself in the first week in November. 

 Having taken notice, in October 1780, 



