VEGETABLE PRODUCTION b. 
195 
still sound and perfect. In the construction of the Yera Cruz 
railroad, the cross-ties and sleepers are made of guapaque, and 
notwithstanding the exposed condition of the superstructure, the 
wood remains unchanged. Both mahogany and cedar are lasting 
timbers, as is satisfactorily proved by the age of the canoes, 
many of which are known to be more than forty years old. Of 
the value of the pine, oak, and cypress, it is, perhaps, sufficient 
to say that there are many of these trees (felled by the Span- 
iards) in a more or less perfect state of preservation, still lying 
in the Rio del Corte, where they serve to recall the faded glory 
of the naval arsenal at Havana. The castarica is also a valu- 
able building timber, which possesses the merit of being inde- 
structible by insects ; and the macaya seems particularly adapted 
for the purposes of hydraulic construction. This latter tree is 
said to have the property of becoming petrified, in proof of which 
there are many now in that state, in the Arroyo de los Urgells', 
one of the tributaries of the Uspanapa, where they were felled 
in 1818, during the -war of the Independencia, to obstruct the 
progress of the troops. The javicue, or jabi, also merits atten- 
tion for its exceeding hardness and durability. This wood is 
incorruptible in water, and is useful for naval construction. 
It is a matter of some regret that the limited time for the sur- 
vey did not admit of any very accurate experiments to demon- 
strate the existence of the teredo navalis in the waters of the 
Pacific. But if the drift-wood on its shores (frequently im- 
bedded in the sand, and submerged for months and years), with- 
out being attacked, be any criterion, there is reason to believe 
that the southern coast of the Isthmus is exempt from this 
scourge. In fact, no proof exists of their presence, and they 
are unknown to the natives. The pholas dactylus is, however, 
found in the waters of the Gulf shore. 
Lastly, as the time of felling has an important influence on 
the durability of timber, it ought, of course, to be duly con- 
sidered ; but, without entering into the analysis of the rules 
observed, it is sufficient to state what those rules are, and the 
effects resulting from their non-observance. " The cutters pro- 
ceed to fell the trees in the wane of the moon ; for, however 
strange, it is a fact well known that the tree is then free from 
