The New York herald., 1878-10-24
THE UNITED STATES SURVEY.
Attempt to Open Up a New
Field for Trade.
COMMERCIAL RELATIONS
How Americans Should Benefit by Inter-
course with the Boliyans.

has recently made very successful survey OF the
Amazon River and who Is one OF the ablest officers
In the navy, 10 spending few days in this city with
bis family preparatory to his going to Europe In
command OF tho United States steamer Enterprise,
which vessel, II viii be remembered. he the
survey. He waited upon to-day at hts
sossy cottage on Catherine street by a COR
respondent OF tho HERALD, Tor the pur-
pose OF gaining some additional inform alton
pertaining to hts important mission TO Brazil which
had not Decn gwen IN the HERALD's correspondence
from Brazil. Captain Seifrdge is looking remarkably
woi alter his VISIT and he evidently enjoyed the trip.
AZ soon as correspo ndent made known his bust
ness ne kindly consented give him idea OF the
importsnt work which had been accom- mplished, al.
though he could scarcely spare the time, as he is
undor orders TO take ommand OF his vessel N0vem
ber /, and In the meantime he has his report to pre-
pare In order transmit TO tho Secretary OF tho
Navy, as mentioned in the Sunday HERALD. Tho ap-
pearance OF his library indicated that he had his
hands full, for end OF manuscript could be seen
upon every hand.
Believing tnat few facts pertaining 10 the way in
whicn tho survey prosecuted would be read with
Interest," your correspondent gathered the following
In regard to the matter from Captain Seridge, and
they substantially recited by that gentleman.
Tho Captain commenced by saying that tho usual
way OF entering the Amazon River by all classes OF
vessels was by way OF the Para Rvcr, and not
through tho mouth OF the river proper The city OF
Para situated estuary OF the ofthat name,
which by many geographers is spoken OF one Of
the mouths OF the Amazon, but, properly speaking,
this is 50, because the Para River is connected
with tho great Amazon by series Of
intricate lagoons or canals up which the tide flows
and down whtch but little OF the waters of the mighty
Amazon dnd their way. These chan nnels, however,
the through which tho trade OF the Ana
Is carried TO and tro from the via Para,
and therefore It here that the survey OF tho en-.
tsrprise commenced.
~ "RUxSISG SURVEY"
The survey was what Is known as a running survey
IN distinction TO what Is known the triang gulated
survey, system adopted survey OF large scale.
or those whore the surveys are liable 10 annual
changes. For instance, very correct map bo
made for a large river by running survey where
u woald take many years to trianguiato the
same, and during this period so many natural
changes would be iiaoie to take place that tho
apguFatton, though correct In theory, would not al
its completion represent the condition OF the
country any better than a running survey, which
would require not moro than one-nith OF the time.
The great necessity OF sach survey. continued Cap
tan Ssliridge, was the correct measurement OF the
speed Of the vessc corrected for all OF tide
current and the distance made during the day, cor.
Yscssd BY accurate liberalization OF tho vessels
position. The OF the recent survey Of the En-
ssrpriss were kept in . book resembling the book
used for similar purpose the land ono side Of
page the course distance speed OF the vessel strength
OF tue current and depth OF water wore noted, wnie
on the opposite side straight line was drawn from
the centre OF the page rcsentiDg tho of
vessel The parallel lines had constant value which
was adopted Al tie beginning OF the survey, hepen-
dent upon ths speed OF the vessel Generally speak
ing they Represented intervals OF ve There
tore she value distapce would be The distance
n 0vs inmates OF time. The course OF the Eutcr.
prise being Oh straignt limo the distance between
any swo points At which bearings OF the same
objects were taken constituted u base line, tho
length OF which depended upon the difference time
between when the bearings were taken. The posi-.
oil the snip Ia relation 10 It's distance from tho
two banks was easily MARKED by drawing them
proper relation the central line OF the page repre-
tho course OF tho vessel. The Captain here
order that your correspondent could better under.
stand the difficult work which ne and hs assistants
hao TO perform Whenever the course Of the vessel
changed this point VAS noticed by the placing Of
tue central line OF the page. Tho soundngs
were taken every i've minutes Az the close Of the
day onicers wns had been fitted by thcir skhl
IN astronomical observations would 60 shor0
anu closely define the position o tho ship by circum
meridian observations Of the north ana south stars
for altitude the Longitude.
The positions daily detcrHined by the observers on
tne Encrprlso rarely varied more than one-ourth Of
mile position, and this error becomes insigni1-
when reduced TO the scale by which ali charts
are drawn, and nappreciabe day after day, because
one small error will correct another.
tt. CAPTAIN sEIyRIDGEs PLAN.
IL WAS considered better plan Tor tho Enterprise
Made,rx River nrst As tho latter ra D.
lazy iaiing u was doubtful whether there was sui.
In len days the rapids Of inc Orna we're feacnsd.
beyond which the piot declined 10 carry tho vessel
p. representing 'hss :. would be osnesroas under.
isw icet OF water on ihe rocks Tho steam
laanen. brought out for thus purpose, was
nttcd up and used for the remainder OF tho
survey Of the river The rapids oi Orns, which
were the terror OF the ooaimsn OF Madeira were
accordingly iriangulated aud surveyed Dy Captain
Seiiridge, who found 10 his surprise that the danger
lay more In Imagination than IN an actual TACT.
found sca,iered over the bottom Of the river, wpcn
caused large whlripoois aud wnich gave
!,se !n 20 apprsns,on 81 dsns. more fanc'iut
water was iound Dstwcen the rocks, sale enough tor
vsastis Of deep draugnI depth OF nve iathoms OF
oi July. Tho fail OF the river from this period pntl
low water In October would be ABOUT eighteen feet
Gated that tho river Is hign about the lst o. juno
Ytom this time II continues to fsil slowly to tho
low n,en water marx A, ali seasons Of Inc yssr N.
Amaxon 10 Davigabe for steamships OF any draugh.
There are 10 be suro dangerous points to bc avoided
but thoy have been accurately determined by tho
survey.
The dry season may be SAID 10 extend from May =
November. Inc rainy season III then usherod In 6J
seveps squalls from The West, accompanied by thun
DER anu lightning, whsh arc followed W iew days
0i Ana weather. Then the rains set in and continue
until April, when they are succeeded by occasional
showers up TO June The dry month Of the year may
be said 70 be July, wbcn little rain makes ap-
peArAnca The wct month is January, sometimes
February Tue ram, however, is al no time severe.
or. not of the drsuching character founu In the
ls,hmus OF Darsn, u rarely lasting more than twelve
hours, ana which IL often succesded W days Of no
weather The temperature OF tne dry season ranges
between eighty anu ninety degrees, whilc In the
season u ranges from seventy 1--we TO eighty nvo de.
grces
The climate OF Bolivia Is snluprious and healthy.
The soil 10 fcrtle anu there scams TO DO no reason,
whcn direct communication is established with tho
united states, why tbero should not be large and
profitable trade inaugurated bet ween the two coua.
tries Wbiic chitls aud lever prevail to some extent
ON the Amazon ana Madeira rivers upon the whole IL
may oe sad 10 DO heaitny country, aud the voyage
up the rivers, a ride on the railroad, anu then q
passage through Bolivia over Tho Andes would ccr-
taiby De one OF great interest," would able tho
tourist to secure much valuable Information.
FRIENDLY BRAzfLIASs AND TRADING.