MIGRATION. 255 



mine in that country, observed numbers of swallows 

 clinging to the timbers of the shaft, seemingly asleep, 

 and on flinging some gravel on them, they just moved, 

 but never attempted to fly or to change their place *." 



The following narrative by M. Achard was com- 

 municated to the Royal Society by Mr. Peter Collin- 

 son. " In the latter end of March," says he, " I took 

 my passage down the Rhine, to Rotterdam. A little 

 below Basil, the south bank of the river was very 

 high and steep, of a sandy soil, sixty or eighty feet 

 above the water. 



"I was surprised at seeing near the top of the 

 cliff, some boys tied to ropes, hanging down doing 

 something. The singularity of these adventurous 

 boys, and the business they so daringly attempted, 

 made us stop our navigation, to inquire into the 

 meaning of it. The waterman told us they were 

 reaching the holes in the cliffs for swallows or 

 martins, which took refuge in them, and remained 

 there all the winter, until warm weather, and then 

 they came abroad. The boys being let down by their 

 comrades to the holes, put in a long rammer, with a 

 screw at the end, such as is used to unload guns, and, 

 twisting it about, drew out the birds. For a trifle I 

 procured some of them. When I first had them, 

 they seemed stiff and lifeless ; I put one of them in 

 my bosom, between my skin and shirt, and laid 

 another on a board, the sun shining full and warm 

 upon it ; and one or two of my companions did the 

 like. That in my bosom revived in about a quarter 

 of an hour; feeling it move, I took it out to look at 

 it ; but perceiving it not sufficiently come to itself, I 

 put it in again : in about another quarter, feeling it 

 flutter pretty briskly, I took it out, and admired it. 

 Being now perfectly recovered, before I was aware, 

 it took flight ; the covering of the boat prevented me 

 * Brit. Zool. App. 



