Northern Times.
Liverpool, Merseyside, England, 1857-11-19 00:00:00

TO THE EDITOR OF THE NORTHERN TIME&

Sir,—The terms used in every art or science should be
explanatory, and should have direct and useful reference
to the purpose which they are intended to devote.
Experience during two centuries has shown us a failure,
which proves this—a failure to be attributed more to
the words used in designation of an art, than to any other
cause.

We all know that what has been called great circle
sailing, is an endeavour to do what every writer upon it
attempts to show is absolutely impossible ! He is obliged,
for his own consistency, to admit that no one cats Gail
upon a great circle ; and that it is only useful in certain
cases. (It has not, as a rule, been properly explained to
navigators, that no obstacles exist to prevent great circle
sailing, which do not equally apply in any other sailing. )
However true this may be, the assertion, coupled with the
terms used, have proved unfortunate for navigation ;
inasmuch, as that a highly advantageous saving of distance
in voyages has been left to the chance knowledge, or
credulity, or prejudices of the many. Nor have recent
writers at all removed these prejudices. When we read
in one author, that " although the arc of a great circle is
the shortest distance, yet to navigate it may be impracti-
cable from the intervention of land, or impossible by
running towards the poles, or unadvisable from prevailing
contrary winds, currents, or dangers lying in the track,'
will not the mere unscientific seamen suppose that these'
disadvantages are peculiar to great circle sailing; forget-
ting that no one can sail upon a continuous Mercator's
course, for similar reasons. And when another writer says
—that those who preceded him are in error, and may
mislead even to hundreds of miles, can we wonder that
British shipmasters, in a very large majority, are indifferent
to great circle sailing altogether, and neglect it? The
bulk of our British merchant ships are, to this day,
navigated on the Mercator's course ; but, it is only from a
misconception of those who, probably, when undeceived,
will gladly avail themselves of e ory facility far shortening
a voyage. To insure this, is my object.
I repeat my already published assertion, that if we
accept the improved means of observing, which better
instruments have afforded us, the art of navigation has, dur-
ing the past 200 years, not advanced, but receded, because
knowledge of the science of spherics, as the proper basis of
navigation, has been neglected; and I should scarcely like
to confess, publicly, how great a neglect of the knowledge
of spheric projection I find to have contributed towards
this!

In works published before the close of the seventeenth
century, the same formulae may be seen ; the same
diagrams as at present in use, and the same course of
preparation in the training of navigators, were properly
eetimated as that, for which I, in 1857, am loudly
contending. Spheric as well as general geometric
projection was then the rule ;—now, it is the exception !
It would be curious to learn if our own Nelson availed
himself of great circle sailing in his memorable pursuit of
Villeneuve, in 1805. and upon other occasions.
It is true, that Towson's excellent tables gave a new
impetus to great circle sailing, but still the nautical public
are in this dilemma :—A question, of a purely spheric
character, has been brought forward prominently, and
even fOrced crudely upon the work of shipmasters; while
principles have been neglected, or, at best, have not been
properly illustrated ; nay, terms and diagrams, which
are positively delusive, are even supposed to justify
legislative enactments. Far be it from me to imply wilful
negligence on the part of either teachers or authorities ;
but where an evil has been detected, we have been too apt
to entangle ourselves with attempts to improve, rather
than to revise and re-cast and supplant practices, which,
in their very operation, condemn themselves.
It is peculiarly illustrative of my remarks, that recently
a generally supposed novelty has appeared in our charts,
where great circle tracks are displayed; and, it seems
strange, that in these days speculation should be allowed
to arise as to the very nature of these curves, considering
that they were engraved on charts 190 years ago ! Now,
it is precisely this outragous distortion of the great circle
track, of which I complain, as it helps to rai e the
prejudices to which I have referred ; not that any
impropriety exists in the drawing and publishing of these
-- • lent it is the so doing, without first
securing to the minds ot those destined. to use alum
a proper fundamental knowledge, which would render
them not merely unobjectionable, but widely useful. When
a mere sailor looks at a Mercator's course, in comparison
with the great circle course, his unprepared mind
conceives at once a natural scepticism as to which is
really the shorter route ; or, as to why it can be shorter ;
while he blunders over this, and remembers that he is told
not to use parallel sailing, because being on a SMALL circle
it gives a larger distance between two places on it than a
GKEAr circle would. Can we wonder at his resolving, on
the spot, to stick by his old notions, and leave such new
fangled fancies to their fate. Nor, as things are, should
we, consistently with the question of preservation of life
and property, desire further to pleplex men, who have
such heavy responsible duties already, but commerce
forces the question imperatively upon us. The British
Empire has nearly 20,000 ships employed in foreign trade.
The profits of their owners are seriously effected by the
length of each voyage ; and if there be any means of
navigating the ocean, whereby a saving of time could be
effected, such ought to have due weight with shipowners,
as a question of economy; and even with underwriters,
as a question of safety ; for the saving of a single hour in
a voyage may often save a days' expence, or a tide, or a
post, or a market ; or may even prevent exposure to a gale,
and consequent total destruction of ship and crew ! That
ship-owners need every aid in point of economy, is
evident from two principal indications; these are—First
The actual position of their ship-masters, whose activity
and integrity control the profits of their owners to a great
degree, at the same time that their owners cannot, on account
of heavy expenses, competition with foreigners, &c., afford
to give their responsible masters en adequate salary; and,
kSecon :qy, let any one count the mast-head brooms in the
cocks, not only of London, but at the out-ports, (e. g. the
West India Export Dock!) With these facts before us
every hindrance to Commercial Maritime prosperity ought
to be swept away ; and I hope the brooms I refer to, as
proving the neels of ship-owners, may be a partial means
of effecting this.
My object is, to remove these hindrances to a more
prosperous state of thiegs, and I see no greater source for
hope than from enabling a commander to save to his owners
many a dsy's expense of victualling and detention by always
sailing on the most easily, practicable, and shortest track.
That he may do so, let him understand as follows :
If a commander comprehends the use of the common globe,
and has one, let him rectify it for the latitude and zenith
(the former, by raising the North or South Pole above the
horizon, according to the latitude; and the latter, by
screwing the quadrant of altitude in the zenith;) then,
if ho brings the ship's place under the zenith, and lays the
quadrant of altitude over the place he is sailing to, and
marks where it cuts the horizon, the point or degree so
cut on the horizon will be the correct great circle course,
until he sensibly changes his position either in latitude or
longitude, rhea he repeats the operation. If, however, he
continues many hours upon this great circle course. which
is always a Tangent to the real curve, he will sail away
from, and at a Tangent, to his great circle. Hence, the
more frequently he changes his course the shorter will be
his route; in other words, the shorter these Tangents are
allowed to be, the greater his progress. So that we want
the best means of enabling a commander to make use of
such shortened Tangents ; accomplish this, and the impos-
sibilizy of sailing upon a great circle becomes very nearly
remedierl. But the common globe is an unhandy
instrument on board ship ; nevertheless, I know sonic
intelligent commanders who would not sail without one.
Now, the patent Sperograph is nothing more than a
paper globs, but on a flat surface, and so constructed in
two parts that the one being moveable upon the other
all problems that can be performed on the globe can be
an'wered on the epherograph, and with very much
increased accuracy To anyone accustomed to a globe,
tne spherograph is understood at a glance. I give very
easy means cf taking out a so-called great circle course;
for, independent of the globular spherogtaph, I give a
simple teble, in which, in the space of five or six
seconds of time, the course is traced under every variety of
question that can possibly occur. Hence the facilities for
shortening the Tangents to be sailed on, are so very
simply managed that I beg respectfully to propose to the
nautical world the abolition of the term "great circle "
as a "sailing ;" and (in order to prevent any more
misunderstanding) the substitution of the term " Short
Tangent Sailing," for such I have resolved to call my
method. S. M. &ROY.
Rockferry, Nov. 6, 1857.

At LEWIS & COMPANY'S, Ranalagh-street.
DOTS are CLOTHED from the Agas of Six to Twenty Year