4i26 I'HILOSOPHICAL TRANSACTIONS. [aNNO I76O. 



on the roofs of large houses, exposed to the morning sun : this they daily do for 

 some time, to collect themselves before they take their flight. 



Next, to confirm this opinion, that the migration of some species of swallows 

 is certain, Mr. C. thinks he has some undoubted proofs. He has often heard 

 Sir Charles Wager, first lord of the admiralty, relate that in one of his voyages 

 home, in the spring of the year, as he came into soundings in our channel, a 

 great flock of swallows came and settled on all his rigging : every rope was co- 

 vered, they hung on one another like a swarm of bees ; the decks and carvings 

 were filled with them ; they seemed almost spent and famished, and were only 

 feathers and bones; but being recruited with a night's rest, they took their flight 

 in the morning. 



Capt. Wright, a very honest man, said the like happened to him in a voyage 

 from Philadelphia hither. But a yet stronger confirmation of the swallows being 

 birds of passage, is the (Observation in Mr. Adanson's history of Senegal, lately 

 published ; which is, as near as may be literally translated, from the author's 

 own words ; viz. * The Gth of the same month (October) at half an hour past 6 

 in the evening, being about 50 leagues from the coast (between the island of 

 Gorea and Senegal), 4 swallows came to take up their night's lodging on the 

 ship, and alighted on the shrouds. He easily caught all 4, and knew them to 

 be the true European swallows. This lucky incident confirmed him in the opi- 

 nion he had formed, that these birds pass the seas to get into the countries of the 

 torrid zone, at the approach of winter in Europe ; and to that purpose he has 

 since remarked, that they do not appear at Senegal but in that season. A cir- 

 cumstance no less worthy of note is, that at Senegal the swallows do not build 

 nests as in Europe ; but lie every night by pairs, or single, in the sand upon the 

 sea-shore, where they rather chuse to fix their habitation than up in the country.' 

 Hist, de Senegal, p. 67. 



This observation, (as it comes from a professed naturalist, and one who went 

 into those countries on purpose to collect what was curious in that way) seems to 

 put the matter out of doubt; and the hearsay stories of ignorant peasants and 

 credulous people are by no means to be put in competition with it. 



Mr. C. was for many years very watchful in taking notice of the times when 

 the swallows leave us, and had twice seen them undoubtedly taking their flight. 

 At two different years, on the 27th and 29th of September, walking in his gar- 

 den at noon, on very clear sunshiny days, and looking up into the sky, at a 

 very great height, he distinctly saw an innumerable number of swallows, soaring 

 round and round, higher and higher, until his eyes were so pained with looking, 

 that he could no longer discern them. 



But as Mr. Klein seems to be so positive, that the hirundo riparia, or sand 



