251 
SUGGEfeTIOKS TO DIRECT RESEARCHES. 
collector to the most useful subjects of investigation, 
and that he may employ his labours to the best advan- 
tage. In regard to Europe, indeed, there is not much 
to°be said, as its general ornithology has been so well 
investigated and so accurately described : much, how- 
ever, remains to he done in respect to the southern 
extremity of Spain, and the whole of Greece and Euro- 
pean Turkey. No one has yet informed us of the pro- 
portion of Spanish birds found on the shores ot the 
opposite continent of Africa ; and what are the birds of 
the latter countries which do not pass the straits of 
Gibraltar? As to the birds of Greece, its numerous 
islands, and the wild and wooded provinces of Turkey, 
we know as little of them as if these countries were situ- 
ated in the heart of Africa. The ornithology of the 
Caspian Sea, and the adjacent provinces, was, indeed, 
investigated by Pallas, but in those days we were not 
accustomed to examine very accurately ; and we question 
much whether that celebrated traveller is correct in con- 
sidering so many of the species he there met with (par- 
ticularly among the land birds) as identically the same 
as those of northern Europe. The annual migration of 
land and water birds from Africa to the shores of the 
Mediterranean and its islands, would furnish a large 
collection to any ornithologist who made a spring trip 
to these countries in the months of Ajiril and May. 
(212.) A ERICA, as being the least known continent, 
would seem to hold out a prospect where the greatest 
discoveries might be made, but this is very problema- 
tical. The arid, naked, dry nature of the soil is alike 
unsuited to insects and birds ; and the obstacles which 
impede the ordinary traveller will be doubly felt by the 
naturalist who attempted to penetrate its central tracts, 
and who would be encumbered with his collections. 
These objections, however, do not apply so much to t le 
more fertile provinces of Asia Minor and the shores o 
Red Sea, neither of which have been visited by any 
modern ornithologist. Mr. Salt, indeed, brought a to 
ably good collection with him from Abyssinia, but the 
