The New York herald. [volume] (New York [N.Y.]) 1840-1920, 1859-01-15

CHART CT THE pRAzIIiAN coAsr-LErTER OF
THE ADMIRAL TO COMMANDER MAuRY-THE AID
OF AMERICAN sHIPMAsTERs REQUESTED.
70 SHRxAsrERs Sourn AMERICAN TRADE VINO ARE
COLLECTING MATERIALS FOR THE WIND AND CURRENT
WARRINGTON OBSERVATORY, Jan. IL, 1859.
Admiral De Chabannes, of the French Navy, has, as will
be by the subned letter. undertaken to construct
upon large scale and with great minuteness series OF
pilot charts rather Of pilot tables Of the coast Of Brazil
which promise TO be Of great value TO the practical nav'
gator To enable that distinguished officer to carry out
this admirable pan vast numbers observations will be
required American navgaors will reap largely OF the
benefits resulting from such tabuaton, whatever they
may be.
therefore request that those trading to the Brazs or
the river who are cooperating with me, will have the
kindness to contribute each his mite to this undertaking.
by sending TO the ADMIRAL Of the French Consul at
Rio extracts from their logs for much OF the voyage Us
may lie between the line and the river.
The extracts should differ from the abstract log IN inns
The abstract log requires the winds be entered three
times day these extracts should give them Tor every
hour.
Navieators who were formerly in that trade may help
on the good work by making extracts from e Ola logs
AN such, if sent to me- will be duly forwarded to RIO All
vessels arriving Rio will, it is hoped, Offer the Admiral
the use OF their logs. NJ. +. NAURY.
LETTER FROM ADMIRAL DE cHABANNEs.
FNGATE LALcEsrE,
To COMMANDER MuRy, DIRECTOR OF THE OBSERVATORY,
WAsHNGroN:-
utility ,he Wind Charts that the British Admiralty has
published, and which nothing than reoast of
the Pilot Charts that contained m your admirable
work Of the 'Sailing Directions"
have made OF them chiefly or the coast Of Brazil
sa"ares Of degrees longitude by degrees latitude coz
spaces too extended especially for navigation wesn
100 leagues from the coast q That the wind stars being
traced with different scales for the divers squares,
inspection of the chart alone does no. suffice for
The obtaining of sufficiently exact appreciation ef the
duration of the Winds and that II is necessary 10 make
proportion before attaining comparative results g. That
The distribution of winds by ttmues not sufficiently
detailed for the Of navigation These remarks have
led me 10 seek the means of extending the work of the
British Atmaltys wind charts of the coast OF Brazil by
bringing observations to bear squares Of deg of
Longitude by deg of latitude, and for each month sepa
yately you have done in your ingenious pilot charts
with the hope that You win aid me With your advice The
great example you have given to the world, by tho
elevated tone of your views, by the immensely OF
searches, has stimulated the ardor OF all those who
interested in the perfecting Of navigation; and
small portion of the globe should be able to add any
thing to the data you have given to sailors OF ali nations
who traverse the oceans.
NY intention is TO determine wha. are the winds that
prevail from Cape ST. Rogue to Ia Plate extending to one
hundred leagues from Shore for every month OF The year.
and by squares OF degree longitude and one degree
latitude. shall not adopt eight hours as the Unit OF tne
but one hour and will seek how many hours during
each month the different winds blow The results which
shall find will be inscribed in tables which viii contain
every month OF the year Tor each square. 20 snail
have many tables there squares-that is 10
say, nearly two hundred for the portion Of the At
f. .c winch w,sh 70 explore ana tne whole WI ~
consult and which will indicate which route he should
follow to obtain the best chances fer favorable wind
and make his the shortest passage. chart accom-
lanyng the pamphlet viii indicate the position OF each
square.
need large number Of observations have already
commenced, by means Of the logs that have been able
procure here. The Brazilian Admiralty has placed al
my disposal all those Of the vessels OF the imperial navy
which have cruised these coasts during the last TWEEN
ty 1--WE years wish to obtain as many as possible Of
other navies and it, amidst the innunerable documents
you have had consult in the construction of pilot
charts, should be enabled get access to those which
relate to the location l have indicated, you would
render great service by procuring me this means OF
multiplying the observations Perhaps might be posi-
bic to have them sent 10 me by the Chief
of the United States naval forces will employ the same
medium to return them My stay this station being
extended to 1860 VIII have ample time for receiving
these documents which would be so precious for the com
pleon Of my work.
take the liberty sir Of indicating to you the manner
IN whSh y ocesG to abstract from the logs
the method meets your appreciation.
trace every ships track on chart of large scala,
which contains the numbered squares, or which here
Remark That have only made squares OF degree
10 aboet 200 miles from the shore outside OF which they
are squares Of two degrees In searching the logs
note, forms prepared fof this work, the number Of
track with the cay and the month. This scrutiny held
all the logs This preparatory work will furnish me ut
completion for each Of the squares certain number
separated by columns it viii be easy to add the hours OF
each wind, which produce totals OF hours, which will
reduce by proportion the hours contained in month.
example will suffice TO make me understood. Let US
euppose that for the square No s 70 30 degrees lon
W. Of Paris to- degrees lat) have 10000 hours Of
observation for the month OF April, Of which 5000
/. winds. 1000 ES.E 000 NE, aud 900 variable
WINDS viii thence concigde that for the month OF APRIL
which contains 40 there VIII be 49, hours OF wind from
the Sc, i44 ES.E, segentytwo Ne, and seventytwo
yarabes. his game process applied to each month VIII
furnish me with the necessary elements wherewith 10 Ill
the tables above mentioned, and Of which enclose
specimen have detailed II all the winds Of com
pass from TWO points 70 TWO points but there would be
great smpihcpton Of the matter il limited myself 10 the
prevailing winds, making sum total Of the winds that
blow but few days in the month would be much
obliged to you for your advice on this head.
The union Of all these tables viii make pamphlet,
which intend emitting Tables indicating the prevailing
winds for each month and FOR each Of degree
(atera the eastern coast Of South America and form
ing supplements TO MaQry's Charts, n. B."
The number placed at the head OF each table indicates
the square on the chart the number on the le Of the
month the number Of observations made, and the number
10 the right he number Of hours.
The comparing Of these divers tables WI show the
yGasor the best route 10 follow and their use VIII be SIM
pie and practicable.
What have undertaken to do sir is merely the extern
sion 10 very small extent Of the very important bors
that you have done for all and which have 50 greatly
helped the art Of navigation, 70 the Of dunn
ishng by nearly onehaf certain voyages II sacn re-
SEARCHES made in all quarters frequenied by veses
there no doubt that many suggestions would he found
20 shorten Their passages around the ocean, and will
always be you, sir, 70 whom the honor will be due be.
cause It was you who enlightened the world TO these
views.
wines some indications on tue currents. should have
been pleased also - note the force % the wind the
peatufc Of 1he water and air. aud the baromerc height
but sirs ogs general wanting the records necessary
for his purpose and 10 viii only BE- when captains shalt
have learned tie mportanceo OF tacse data by conforming
20 the form Of the log which you gwen that we shall
be a)e 20 obtain these Interesting details.
end this letter sr BY )eegng YOU 10 It's length,
aud 10 accept The expressions u nay high consd ration
o. De CHABANNfsS.
The Vice Admiral Cofnmandertn-Ch eff Of the French
Naval Division Of Brazil ana In Plata