Manchester Mcjiioirs, Voi. Hit. (1909), No. lij. 5 



miles an hour ; in a contrary direction — with a " Head- 

 wind " — it would have made no progress at all, like the 

 ducks over the mere. If merely flying lazily round in a 

 50 feet circle it would have travelled in one hour 50 miles 

 which is the velocity of the medium supporting it. 



I must now refer to Mr. W. E. Clarke's very important 

 report of the Committee (Prof A. Newton, Messrs. 

 J. Cordeaux, J. A. Harrie-Brown, VV. E. Clarke, 

 R. M. Harrington, and Rev. E. P. Knubley) appointed by 

 the British Association to investigate the subject of 

 migration. It appears in full in the Report of the 

 Liverpool meeting, 1896, pp. 451 — 477. It is here stated 

 that meteorological conditions have been closely studied 

 in relation to migration. Under the heading of Winds, 

 occurs the statement that " The importance attached to 

 winds in connection with bird migration, has hitherto 

 been much overestimated by popular writers, and their 

 influence, such as it is, misunderstood. The conclusions 

 to be drawn from a careful study of the subject are 

 (i) that the direction of the wind has no influence what- 

 ever as an incentive to migration ; but that (2) its force is 

 certainly an important factor, inasmuch as it may make 

 migration an impossibility, arrest, to a greater or lesser 

 degree its progress, or even blow birds out of their courses. 

 It is, however, a fact that particular winds almost invari- 

 ably prevail during the great autumnal movements, and 

 these have hitherto been considered by some as the direct 

 incentives to such migrations. Such is not the case, and 

 it may at once be stated that these supposed favourable 

 breezes are simply another direct result of the pressure 

 distribution favourable to the movements." 



This last statement detracts very considerably from the 

 value of those parts of the Report that treat of meteorolo- 

 gical conditions. The breezes are 7iot in this instance the 



