[ 28 S ] 
Monf. de Buffon does not, in this account of his 
experiment, date the time during which the birds 
were confined j but as the trial muft have been made 
in France, the fwallows which he procured could 
not be expected to be torpid either in an ice-houfe* 
or any other place, becaufe the feafon for their being 
in that date was not yet arrived. 
I cannot alfo agree with M. de Buffon that thofe 
birds which were fhut up the longed time died 
through cold, as he fuppofes,. but for want of food, 
as he neither fupplied them with any flies,, nor, if he 
had, could the fwallows have caught them in the 
dark a very fhort faft kills thefe tender animals, 
which are feeding every inflant when on the 
wing. 
It therefore feems not to follow from this, or any 
other experiment, that fwallows mud. neceflarily 
migrate (as Monf. de Bufifon fuppofes) to the coad of 
Senegal. 
* The very name of an ice-houfe almoft fir ikes one with a 
chill ; I placed, however, a thermometer in one near Hyde Park 
Corner, on the 23d of November, where it continued 48 hours, 
and the mercury then flood at 43! by Fahrenheit’s fcale. 
This is therefore a degree of cold which fwallows fometimes- 
experience whilft they continue in fome parts of Europe, without 
any apparent inconvenience ; and it fhould feem that the cold, 
vapours which may arife from the included ice, fink the ther- 
mometer only y or 8 degrees, as the temperature in approved 
cellars is commonly from or 51 throughout the year. 
Sir William Hamilton informs me, that he hath frequently 
feen fwallows in the winter between Naples and Puzzuoli, when- 
the weather was warm ; as does Mr. Hunter, F. R. S. that he 
hath obferved them during the fame feafon, on the confines of 
Spain and Portugal. It fhould feem from this, that very mild* 
and warm weather for any continuance always wakes thefe birds 
from their flat* of torpidity. 
Swallow* 
