The Portland daily press., 1885-12-17
COAST DEFENcEs.

Gen. John Newton, chief of engineers of
the United States Army, has recently sup
plemented Mr.. Tilden'S letter in regard
to our coast defences with an inter
esting account Of their present condition,
their needs and the length of time that would
be required to put them in condition to pro-
tect our cities from the iron clad ships of for
eign nations. Gen. Newton says the popu-
lar notion that in few months our coast de-
fences could be made sufficiently effective to
resist powerful enemy is entirely errone-
Gus. 1t would require many years for us to
get together modern guns, to say nothing of
the work of constructing forts and batteries.
Ten or twelve years at least would be need
ed to put our coast in adequate state of de-
fence. The kind of defences required would
vary with the Importance of the port to be
protected. For port Of minor Importance
earth batteries, with guns mounted en- bar
bette, would in general be sufficient For
the more important ports where guns of the
greatest power are required, reversible tur-
rets, and in some cases steel armored case
mated batteries should be constructed The
armor whenever required in forts may be Of
railroad iron, compound plate or steel plate
or chilled cast iron. But the character of
the guns is of more Importance than the
style of the Notifications Gun making is
making more progress than the construction
of ironclad ships. A little while ago thirty
thousand foot tons of energy in the projec-
tile was considered to constitute a powerful
: gun, but they are building guns now which
will give sixty-one thousand foot tons, and
they have in contemplation the construction
Of gun with ninety thousand foot tons of
energy. The destructive power of guns has
increased, and is increasing beyond the buoy
ant power of ships, SO that vessels can no
longer carry the armor upon them sufficient
to resist penetration. We have, therefore,
the advantage on land that we can make our
batteries, Of whatever material constructed,
sufficiently thick to resist the most powerful
guns that can be built; and if the weight of
guns progresses in the near future as much
as in thepast, we will be using guns on land
whichecannot be utilized on board Of ship.
The torpedo system will undoubtedly play
a prominent part in our defenceS. Gen.
Newton's idea is that lines of mines operated
by electricity can be made so formidable
that no ship can pass them. But these sub
marine mines cannot defend themselves
against attempts to countermine them or to
drag off the cables and other electrical at
tachments, and SO, of course their neutraliza-
ton or destruction would be only question
of time, unless some means were taken to
keep off the enemy. Mines are needed to
prevent fleet from running the batteries,
and batteries are necessary to prevent a feet
from destroying the mines. Both of them
are essential Gen. Newton thinks with
proper encouragement our manufactures
would soon have the plant and skill necessary
to construct the guns of the best and most
powerful class.
Such system of defences as he suggests
he believes would stand until the whole art
of war is changed The gun of the pres
ent design will be a structure on correct SCI
entifc principles, and future improvements
will be very gradual, and will not revolu-
tionize by any sudden increase the scale Of
yelocities now given to proiectiles. 1t would
appear, therefore. that the time had come to