188 GILBEKT WHITE OF SELBOENE 1770 



is the only Describer I ever met with that conveys some 

 precise idea in every word or Term he makes use of. Though 

 your Brother is forestalled in the discovery, yet his ascertain- 

 ing the winter residence of this new species of swallow will 

 probably be attended with considerable advantages to 

 natural History ; as it must in great measure, if not entirely, 

 overturn that, in my opinion, very absurd hypothesis of 

 swallows living all Winter in a dormant state under water. 

 I call this hypothesis absurd, as it asserts a body, bulk for 

 bulk, specifically lighter than water, sinks to the bottom of 

 a pool or river, contrary to a known and allowed principle 

 in Hydrostatics — and farther — why may we not reason, by 

 analogy, from your Brother's discovery, that those Species 

 of Hirundines which frequent and affect warmer summer 

 situations, than the summits of the Alps, require a greater 

 degree of warmth in winter, and of course retire at their 

 usual times of migration into more southern Latitudes ? 

 I am inclined to believe, was the experiment fairly made, 

 that most of the known species of this Genus would be 

 discovered along the shores of Africa ; nor do I in the least 

 doubt the veracity of Adanson,* when he asserts that He 

 observed vast multitudes of European swallows in the 

 neighbourhood of Senegal and Goree. 



After I left your hospitable roof, Kew and Hammersmith 

 were the scenes of my amusement, and highly entertained 

 I was at each of these places, at the former with Plants, 

 at the latter with Insects. I made a considerable addition 

 to my collection in each of these Branches. Lee was greatly 

 pleased with the Panorpa coa and the Vespa crabroni con- 

 gener, which He had not seen before. I told Him I flattered 

 myself I had interest with you to procure him a specimen 

 of each, and perhaps of some others which were new to him. 



* Michel Adanson, author of * Histoire Naturelle de S^n%al avec la 

 relation abreg^e d'un voyage fait en ce pays 1749-53,' published in Paris 

 in 1757. An English translation appeared in London in 1759. — A. N. 



