LVI.] 
district where they are bred, they must nndergo vast devasta- 
tions somehow, and somewhere ; for the birds that return 
yearly bear no manner of proportion to the birds that retire. 
House-martins are distinguished from their congeners by 
having their legs covered with soft, downy feathers down to 
their toes. They are no songsters ; but twitter in a pretty 
inward soft manner in their nests. During the time of breed- 
ing they are often greatly molested with fleas. 
Sb:LBORNE, Nov. 20, 1773. 
LETTER LVI. 
TO THE HONOURABLE DAINES BAPdllNGTON. 
I RECEIVED your last favour just as I was setting out for this 
place ; and am pleased to find that my monograph met with 
your approbation. My remarks are the result of many years 
observation ; and are, I trust, true in the whole : though I do 
not pretend to say that tliey are perfectly void of mistake, or 
that a more nice observer might not make many additions, 
since subjects of this kind are inexhaustible. 
If you think my letter worthy the notice of your respectable 
society, you are at liberty to lay it before them ; and they will 
consider it, I hope, as it was intended, as a humble attempt to 
promote a more minute inquiry into natural history ; into the 
life and conversation of animals. Perhaps hereafter I may be 
induced to take the house-swallow under consideration ; and 
from that proceed to the rest of the British liir undines. 
Though I have now travelled the Sussex Downs upwards of 
thirty years, I still investigate that chain of majestic mountains 
with fresh admiration year by year ; and think I see new 
beauties every time I traverse it. This range, which runs from 
Chichester eastward as far as Eastbourne, is about sixty miles 
in length, and is called the South Downs, properly speaking, 
