from the Paso of the Sarabia to its mouth : from the confluence 
of the Chimalapilla to that of the Sarabia we floated down on 
rafts ; and, in laying down the course, we determined astrono- 
mically the latitudes of five points. The intermediate places were 
observed by compass, estimating the distances by the time em- 
ployed in passing along them, which was the only method we 
could adopt, owing to the matted state of the forest along the 
banks ; and in those places where some of the loops made by 
the river approach each other in the branch of the Apotzongo, 
the ground was examined on foot by paths which we had to 
cut for ourselves. 
Not being enabled to determine by observations the position 
of the mouth of the river, we have adopted that laid down by 
the Spanish naval officers. 
