NATURAL HISTORY OF SELBORNE 65 



but still I am pleased to find you have discovered it in Lincoln- 

 shire, for the reason I have given in the article of the white 

 hare. 



As a neighbor was lately ploughing a dry, chalky field, far 

 removed from any water, he turned out a water-rat, that was 

 curiously lain up in a hybernaculum artificially formed of grass 

 and leaves. At one end of the burrow lay above a gallon of 

 potatoes regularly stowed, on which it was to have supported 

 itself for the winter. But the difficulty with me is how this 

 amphibius mus came to fix its winter station at such a distance 

 from the water. Was it determined in its choice of that place 

 by the mere accident of finding the potatoes which were 

 planted there ; or is it the constant practice of the aquatic rat 

 to forsake the neighborhood of the water in the colder months ? 



Though I delight very little in analogous reasoning, know- 

 ing how fallacious it is with respect to natural history ; yet, in 

 the following instance, I cannot help being inclined to think 

 it may conduce towards the explanation of a difficulty that I 

 have mentioned before, with respect to the invariable early re- 

 treat of the hirundo apus, or swift, so many weeks before its 

 congeners ; and that not only with us, but also in Andalusia, 

 where they also begin to retire about the beginning of August. 



The great large bat (which by the bye is at present a nonde- 

 script in England, and what I have never been able yet to pro- 

 cure) retires or migrates very early in the summer; it also 

 ranges very high for its food, feeding in a different region of 

 the air; and that is the reason I never could procure one. 

 Now this is exactly the case with the swifts; for they take 

 their food in a more exalted region than the other species, and 

 are very seldom seen hawking for flies near the ground, or over 

 the surface of the water. From hence I would conclude that 

 these hirundines and the larger bats are supported by some 

 sorts of high-flying gnats, scarabs, orpkalcena, that are of short 

 continuance ; and that the short stay of these strangers is reg- 

 ulated by the defect of their food. 



By my journal it appears that curlews clamored on to 

 October 3ist; since which I have not seen nor heard any. 

 Swallows were observed on to November 3rd. 



