35 
quently impeded the prosecution of the survey. An almost 
incessant wind either blew down or inclined obliquely the 
landmarks, or causing the instruments to oscillate violently, 
disturbed the observations; and lastly, with the exception of 
a few moments before the rising of the sun and after its set¬ 
ting, a dense flickering vapour hid from view the objects which 
served as guides, whilst the refractions, especially the lateral 
ones, produced the most strange illusions. 
The Zapoteco soldiers, who carried the chains, evinced a 
wonderful degree of intelligence, and in a very short time they 
became as proficient as could be wished. 
After the necessary corrections to the mean sums of the sepa¬ 
rate measurements, the total length of the base was obtained, 
showing an aggregate distance of 16,930 metres or 10J miles. 
The survey commenced at the villages of St. Mateo and San¬ 
ta Maria, referring to the points trigonometrically fixed. The 
same was afterwards done with the coast of the Pacific as far 
as the Morro, and the tract of country between the sea and 
the town of Tehuantepec, including the course of the river by 
which it is watered, and which flows afterwards into the ha¬ 
ven of Las Yentosas. 
It has been suggested that this bay might be used for the 
purpose of anchorage ; but, on examination, it was found that 
its small size, as well as its exposure to the prevailing .winds, 
made it totally unfit for such purpose, even supposing it were 
deep enough. The other haven to the west of the Morro is also 
too much exposed, and filled with dangerous reefs; and though 
it be true that Cortes launched a few vessels in the first of 
these coves, it is well known that in those times vessels were 
built of small dimensions ; and probably he made use of that 
spot, not because he considered it fit and safe for such an ope¬ 
ration, but simply because it was the only one near at hand 
where it could be at all accomplished. The sands carried down 
by the waters of the Tehuantepec are now fast accumulating 
in the bay, and before long it will be completely obstructed. 
The Commission then proceeded to San llionisio Tepehua- 
zontlan, and Sr. Moro carried on his observations in Camote- 
pec and Juchitan, and proceeded to reconnoitre new points, in 
c 2 
