HOUSE-MARTINS. 165 



shell of this nest seems to be formed of such dirt or loam as 

 comes most readily to hand, and is tempered and wrought 

 together with little bits of broken straws, to render it tough 

 and tenacious. As this bird often builds against a perpen- 

 dicular wall, without any projecting ledge under it, it requires 

 its utmost efforts to get the first foundation firmly fixed, so 

 that it may safely carry the superstructure. On this occasion 

 the bird not only clings with its claws, but partly supports 

 itself by strongly inclining its tail against the wall, making 

 that a fulcrum ; and, thus steadied, it works and plasters the 

 materials into the face of the brick or stone. But, then, that 

 this work may not, while it is soft and green, pull itself 

 down by its own weight, the provident architect has prudence 

 and forbearance enough not to advance her work too fast ; 

 but, by building only in the morning, and by dedicating the 

 rest of the day to food and amusement, gives it sufficient 

 time to dry and harden. About half an inch seems to be 

 sufficient layer for a day. Thus, careful workmen, when 

 they build mud-walls (informed at first, perhaps, by these 

 little birds), raise but a moderate layer at a time, and then 

 desist, lest the work should become top-heavy, and so be 



Lord Albemarle's estate, and he was in the constant habit of visiting it, and 

 took much interest in the proceedings of the swallows. In reading the above 

 account, which has been given in Lord Albemarle's words, it is almost impos- 

 sible not to be struck with the following facts : 



1st, That the swallows must have discovered and worked up a sort of clay 

 or earth which would stand heat. 



2nd, It is, I think, clear, that instinct alone would not have taught them to 

 do this. Let me then ask those who deny any faculties to the animal creation 

 beyond instinct, what faculty induced the birds to alter their original mode of 

 procedure ? 



3rd, On returning to the kiln the second and third years, the swallows must 

 have kept in their recollection, not only the fact that the earth instinct had 

 taught them to use in building their nests would not bear the heat of the kiln, 

 but they must also have remembered the sort of earth or clay which was 

 requisite, and also the necessity of making use of it in that peculiar place. 



Mr. White has elsewhere remarked, that philosophers have defined instinct 

 to be that secret influence by which every species is impelled naturally to 

 pursue, at all times, the same way or tract, without any teaching or example ; 

 whereas reason, without instruction, would often vary, and do that by many 

 methods which instinct effects by one alone. If this definition between 

 instinct ar,d reason is correct, the above mentioned fact would seem to entitle 

 these swallows to be considered as possessed of no ordinary degree of sense and 

 intelligence, if not of something approaching to reason. ED. (Gleanings.) 



