The New York herald., 1873-08-31

AAAo PAo'"o" vi PAouS CoPACn, oo well III Iuo otu-
dio as in the pulpit
New Safeguards OF Navigation.
One. of the most important papers recently
contributed to science was read on the 22d
instant before the American Association, at
Portland, by Professor William A. Rogers, on
the safety of ships at sea. The elaborate data
brought forward by the author of the paper
reveal the startling fact that the percentage of
wrecks since 1858 has been steadily increasing.
In the case of British shipping the percentage
since that year has alarmingly risen from
thirty-eight to ffty-seven, while in one year,
with decrease of four per cent in the number
of ships, the wreckage was twenty-one per
cent in excess. The conclusion reached by
the Professor was that nearly three-fourths of
these disasters at sea were preventable, and he
showed, statistically, that very large proper
ton of vessels go to the bottom that the
owners may get the insurance
But the chief value Of the paper was the
light it sheds upon the chronometric sources
of error on board ship and the demonstration
of the unreliabiity of all nice determinations
of vessels position. To this prolific source
of marine casualties is doubtless rightly
charged the augmented percentage of wrecks,
and nothing of greater moment to commerce
and mankind can be discussed. A few days
ago we had the loss Of the City of Washing
ton, without any satisfactory reason for it,
while it is certain that had that vessel lost her
reckoning and every instrument by which to
determine it her commander might have
safely navigated her inshore by the water
thermometer and the lead. The time has ar
rived when navigators sailing on the great
thoroughfares of trade, instead of trusting
only to the guidance and glimmer of the stars
overhead-a dependence which ever fails when
most needed in the hour of storm or fog
should also employ the thermometer and
learn to feel their way in almost perfect
security. Franklin, with his great practical
mind, discovered nearlya century ago that the
seaman, in approaching our coasts, could
steer with the greatest certainty in the blacklist
weather by thermometric tests of the warm
Gulf Stream current and its cold counter
stream. His friend Williams, who made o sea
voyage from Boston to Norfolk to try the
scheme, sailed almost as safely without COM
pass as with one, and his experience has ever
since been cited by the most eminent naviga-
tors as conclusive proof of the great value of
thermometrical navigation. When the present
current charts, accessible to all mariners, are
properly studied they will enable them to
mark most clearly the position of the ship
when other determination is impossible-as
clearly, to use old Williams words, as if ''the
stripes of water were distinguished by the
colors red, white and blue"
But, besides this thermometric guide, the
befogged or weather-ridden seaman, when
nearing land, has the sounding line to tell him
within few miles just where he is. The
splendid researches in the deep sea are rapidly
progressing and are intensely practical, for we
may hope they will ultimately give us photo
graphic chart of the sea bottom, it's
valleys and its basins, its banks and plateaus
and all its topography SO fully that sailing
master ought to be able to very nearly tell his
position by the lead. Professor Pierce of
the Coast Survey, in discussing Professor
compulsory by law, will prove the only safe
guard of ships, and showed that by the incest
astronomic determinations the navigator may
count usually on an error Of twenty miles, and
very often as much as sixty miles, without
taking into account errors from compass de-
Walton and other sources. The American
coast generally shelves gradually into the At
lantic, so much so that our best sailing direc-
tons assure the cautious mariner he may,
with the lead and chart, find the marks under
foot SO plain that he cannot, if he will
try them, get unknowingly into the
dangers Of the shore. There can be
no doubt that the agitation Of the
subject discussed by the Association at Port
land will do great good. But it suggests, what
the HERALD, as echoing the voice of the people,
has often contended for, extensive government
deep-sea explorations and surveys and other
similar researches for obtaining data requisite
for more accurate and complete ocean-current
charts. If Professor Pierce's plan of making
lead navigation compulsory by law, under
given circumstances, were agitated by the un-
Sol"AioeiS ohu oAe press, VIC HiSII De SpdIeu
many such unutterable horrors as only yester-
day, it seems, the telegraph flashed to us
from Meaghers Rock. The government,
through its various well-prepared bureaus, as
well as through its navy, Coast Survey and
through special expeditions sent out, cannot
too soon begin the work of submarine survey
and cartography and the exploration of all
oceanic phenomena the knowledge of which
would make the track of the mariner on the
high seas as easy to find as the path Of the
Western woodsman through the forest after
the trees have been blazed by his axe.