52 A JOURNEY IN BRAZIL. 
observations on the action of animals under these novel 
circumstances. The following extract is from his notes. 
" The effect of the waning light on animals was very 
striking. The bay of Rio is daily frequented by large num- 
bers of frigate-birds and gannets, which at night fly to the 
outer islands to roost, while the carrion-crows (urubtis) 
swarming in the suburbs, and especially about the slaughter- 
houses of the city, retire to the mountains in the neighbor 
hood of Tijuca, their line of travel passing over San Cbristo- 
vao. As soon as the light began to diminish, these birds 
became uneasy ; evidently conscious that their day was 
strangely encroached upon, they were uncertain for a mo- 
ment how to act. Presently, however, as the darkness in- 
creased, they started for their usual night quarters, the water- 
birds flying southward, the vultures in a northwesterly di- 
rection, and they had all left their feeding-grounds before the 
moment of greatest obscurity arrived. They seemed to fly 
in all haste, but were not half-way to their night home when 
the light began to return with rapidly increasing brightness. 
Their confusion was now at its height. Some continued 
their flight towards the mountains or the harbor, others 
hurried back to the city, while others whirled about wholly 
uncertain what to do next. The re-establishment of the 
full light of noon seemed to decide them, however, upon 
making another day of it, and the whole crowd once more 
moved steadily toward the city." 
The cordial interest shown by the Emperor in all the 
objects of the present expedition is very encouraging to 
Mr. Agassiz. So liberal a spirit in the head of the govern- 
ment will make his own task comparatively easy. He has 
also seen several official persons on business' appertaining 
to his scientific schemes. Everywhere he receives the 
