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charged with moisture, whilst, on the other hand, those from the 

 north, north-east and east are, as a rule, very dry. Winds from 

 the south-east, as regards the amount of rain which accompanies 

 them, are very variable, but the local observations of the writer 

 tend to establish the fact that a south-east wind of three or four 

 days' duration culminates in a downfall. 



In presenting evidence in favour of his theory that south-east 

 winds are the most favourable conditions to the performance 

 of migration, Herr Gatke has been at considerable pains in 

 obtaining statistics that these winds prevailed over a vast tract 

 of country lying to the east of Heligoland during certain years 

 when the island was especially visited by a large number of birds 

 which he regards as migrants from far eastern Asia. However 

 interesting these tables are, their value is much diminished by 

 the absence of negative data. How are his readers to know 

 whether or not in other years, when the so-called visitors from 

 the far east did not visit, or only visited the island in very small 

 numbers, south-east winds did not prevail over the same tract of 

 country for nearly the same period? Another point must be 

 noted. Herr Gatke frequently refers to Eichard's Pipit as a 

 visitor from the countries bordering on the Amoor River, or the 

 shores of the Sea of Ochotsk ; he also refers to the Yellow-browed 

 Warbler in somewhat similar language, these two species being 

 supposed to be particularly affected by these south-east winds. 

 Now it does not seem to have occurred to him that a south-east 

 wind blowing in the districts named must have a very different 

 nature from the same wind at Heligoland. In the first instance 

 it will have passed over the Pacific, and so probably have become 

 densely charged with vapour, like the south-west winds of our own 

 islands ; and, in the second place, before reaching his observatory 

 it will have traversed large areas of land, and in the meantime 

 have shed its moisture on the intervening countries in the form of 

 rain. 



To take the tables themselves. It will be found that on 

 examination of the statistics presented, though the preponderance 

 of winds during the first-named year, viz., 1847, blew from the 

 quarters said to be favourable to migration, still in the ninety- 

 one days under notice eighty-six observations of unfavourable 



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