34 
and the preliminary arrangements occupied it until the 2nd of 
June. 
The possibility of effecting a communication between the 
two oceans through the Isthmus may be considered under four 
different aspects. 
1 . By a road. 
2. By a canal for barges only. 
3. By these two means combined. 
4. By a canal of great dimensions, which would afford a tran- 
sit to the loaded vessels themselves from sea to sea. It is 
natural to suppose, that this plan being by far the most ad- 
vantageous was that to v/hich attention was chiefly directed. 
All accounts agree in the facility with which the river Coat- 
zacoalcos might be rendered navigable, at least so far as its 
confluence with the Sarabia ; therefore the space which it was 
most important for the Commission to explore was that inter- 
vening between this confluence and the shores of the Pacific. 
The rains appeared to have set in on the mountains (Sierra), 
which prevented the possibility of exploring them, and as 
time was limited, it was resolved to take advantage of it by com- 
mencing proceedings on the southern side of the Isthmus. 
With this view a rapid excursion on the coast was made, and 
the ground that divides the villages of San Mateo and Santa 
Maria, appeared well calculated for the measurement of a line 
to be used as the basis of the trigonometrical operations ; and 
consequently the exploring party established their residence 
at Sail Mateo. 
Messrs. Ortiz and Orbegozo had discontinued the soundings 
of the lakes and the Boca Barra (bar entrance) of St. Francisco, 
because they could not find a boat for the purpose. This 
want was at once provided for by adapting a sail, oars, and 
helm to a common canoe. 
] iandmarks were erected in those places which appeared the 
most fit as vertexes of the primary triangles. The ground for a 
base line was finally selected on the beach, which hajipcning 
to be remarkably level, was admirably adapted for the purpose. 
The tracing of the base was an operation attended with im- 
mense diflicultv. The rainv season had commenced and fro- 
