RAIN MIGRATION. 107 



hinc circa plenilunium potissimum mensis Octobris plerumquc 

 Austriam transmigrate Tune rursus circa plenilunium potissimum 

 mensis Martii per Austriam matrimonio juncta ad septentrionalcs 

 provincial redit" For the whole passage (which I have 

 abridged) see Elenchus, $c. p. 351. This seems to be a full 

 proof of the emigration of woodcocks ; though little is proved 

 concerning the place of their breeding. 



P.S. There fell in the county of Rutland, in three weeks 

 of this present very wet weather, seven inches and a half of 

 rain, which is more than has fallen in any three weeks for these 

 thirty years past, in that part of the world. A mean quantity 

 in that county for one year is twenty inches and a half. * 



LETTER XLII. 



TO THE HON. DAINES BARRINGTON. 



FYFIELD, near ANDOVER, February 12, 1771. 



DEAR SIR, You are, I know, no great friend to migration ; 

 and the well-attested accounts from various parts of the king- 

 dom seem to justify you in your suspicions, that at least many 

 of the swallow kind do not leave us in the winter, but lay 

 themselves up, like insects and bats, in a torpid state, and 

 slumber away the more uncomfortable months, till the return 

 of the sun and fine weather awakens them. 



But then we must not, I think, deny migration in general ; 

 because migration certainly does subsist in some places, as my 

 brother in Andalusia has fully informed me. Of the motions 

 of these birds he has ocular demonstration, for many weeks 

 together, both spring and fall ; during which periods, myriads of 

 the swallow kind traverse the Straits from north to south,f and 



* The average quantity of rain, which falls annually, has been calcu- 

 lated at between thirty-one and thirty-two inches.* In Scotland, it 

 varies, as in all other countries, with the locality. In Glasgow, it is 

 thirty-one inches; Dumfries, thirty-one inches ; and Dalkeith, twenty-five 

 inches, making an average between thirty and thirty-one inches, or 

 twenty-eight cubit feet of water. Countries adjacent to the coast of an 

 extended ocean have usually more rain than inland districts. In some 

 parts of India it is from one hundred and three to one hundred and twelve, 

 but the average is eighty-five inches annually En. 



f The migration of swallows is not confined to Britain, for they 

 appear to be influenced by a general law in every variety of climate. It 

 lias been satisfactorily proved, that swallows leave even the most extreme 

 southern parts of Europe, as the kingdom of Naples, Sicily, the Morea, 

 &c. and migrate to Africa and Asia. Mr Rae Wilson gives us positive 



