250 THE FACULTY OF SCENT IN THE VULTURE. 



effluvium would always be driven to one quarter in the tropics, where 

 the trade-winds prevail. Often, at the very time that the clouds are 

 driving from the north-east up above, there is a lower current of 

 air coming from the quarter directly opposite. This takes place 

 most frequently during the night-time, in or near the woods ; and 

 it often occurs early in the morning, from sunrise till near ten o'clock, 

 when the regular trade-wind begins to blow. Sometimes it is 

 noticed in the evening, after sunset ; and now and then, during the 

 best part of the day, in the rainy season. In Guiana there is a tree 

 called hayawa : it produces a deliciously-smelling resin, fit for in- 

 cense. When the Indians stop on the banks of a river for the night, 

 they are much in the habit of burning this resin for its fine and 

 wholesome scent. It is found in a hardened lumpy state, all down 

 the side of the tree out of which it has oozed. It is also seen on 

 the ground, at the foot of the tree, incorporated with the sand. 

 When we had taken tip our nightly quarters on the bank of the 

 Essequibo, many a time we perceived this delightful fragrance of 

 the hayawa, which came down the bed of the river to the place 

 where we were, in a direction quite opposite to the trade-wind. My 

 Indians knew by this that other Indians were encamped for the 

 night on the river-side above us. 



When the eruption took place in the Island of St Vincent, in the 

 Carribbean Sea, in 1812, cinders and other minor particles of matter 

 were carried nearly, if not fully, two hundred miles to windward, and 

 were said to have fallen at or near Barbadoes. Had there been a 

 carcass in a state of decomposition at the place during the time of 

 the eruption, no doubt the effluvium arising from it would have been 

 taken to windward by a temporary counter aerial current ; and a 

 vulture in Barbadoes might probably have had pretty certain infor- 

 mation, through his olfactory nerves, that there was something good 

 for him in the Island of St Vincent 



Vultures, as far as I have been able to observe, do not keep to- 

 gether in a large flock when they are soaring up and down appar- 

 ently in quest of a tainted current. Now, suppose a mule has just 

 expired behind a high wall, under the dense foliage of evergreen 

 tropical trees ; fifty vultures, we will say, roost on a tree a mile from 

 this dead mule : when morning comes, off they go in quest of food. 



